Where some of her colleagues teach, she has the power to inspire - all of which makes her behaviour outside the classroom rather surprising. When this inspirational powerhouse comes in contact with her headteacher, she becomes a quivering wreck.
She gets tongue-twisted and flustered, says things she does not mean to say, and feels completely out of her depth. Afterwards, she spends sleep-less nights going over all her blunders and mentally flagellating herself.
No doubt the head actively cultivates the unsettling effect she has on her staff. But Cathy's problem is not confined to that relationship. Her feelings of embarrassment and worthlessness crop up when she sees the doctor, at parties where she does not know others, and in other situations where she feels she is being judged.
So while to her pupils, friends and acquaintances she is bubbly, funny, and in control, to those in positions of authority or who have no relationship with her at all she must come across as a frightened mouse.
What is her problem? It is called low self-esteem, and it is no stranger to the teaching profession. Publicly accountable and blamed for the evils of the world like no other public servants - apart from politicians - many teachers experience feeling belittled and undermined. But whereas most can compartmentalise these assaults, seeing them as something coming from outside, others like Cathy tend to internalise them. They blame themselves for having basic, inherent flaws that attract negative responses.
They do so to their detriment. Sheila Ernst, psychotherapist, author and founder member of the London Women's Therapy Centre, maintains that "if teachers deny that they're under attack as a profession, it will be difficult for them to regain their self-esteem".
But she also warns against over-simplistic explanations. "How you feel about yourself isn't all about social realities. There are obviously constitutional factors such as heredity and past history that work in combination with social pressures to cause you to feel the way that you do."
Being able to understand why you feel the way you do can be the first step to feeling more positive about yourself. Ms Ernst suggests the strategy of asking yourself questions. "Take the time to ask 'why am I so weedy? What's in my history that may be causing me to feel like this? What does this person or situation remind me of? Am I being a little girl? Does this person remind me of someone in my past?' "
For instance, Cathy's problem with her headteacher and others she perceives as being superior to herself could have something to do with her tempestuous relationship with a tyrannical and occasionally violent father.
According to Ms Ernst: "If you can identify what's undermining you, you can buy yourself a bit of space to think through some strategies for dealing with it. You don't have to do years of therapy to identify your behaviour as irrational. Once you understand what's happening, you may be able to devise a plan for dealing with your problems yourself."
Another approach she suggests is joining a group, but those who do so should not expect to raise their self-esteem too quickly. "The idea of feeling better instantly is silly. But one of the good things about people getting together to talk about these issues is that you discover that others have similar difficulties to yours.
"That helps you to realise that your view of yourself may be more depressed than it needs to be. Also, seeing yourself through others' eyes can show that you're being unduly critical about yourself."
If you do not have the time or the inclination to join a group, there is certainly no shortage of books to help you on your journey of self-discovery and acceptance. Psychologist Susan Jeffers's own odysseys through depression and low self-esteem to happiness and confidence have made her a best-selling author of several self-help books in the United States. One, Feel the Fear and Do it Anyway, has sold a million copies.
Ms Jeffers is a great believer in positive thinking. Her voice, even on the telephone from Los Angeles, transports me from my characteristic Eeyore-ishness to believing that I can do anything - at least for the duration of our conversation. She is a testament to the power of mind over matter.
Ms Jeffers has made it through a devastating divorce and mastectomy, and now feels that she has a lot to give the world. "I used to be quite pathetic," she says. "Even when I graduated with a doctorate, I was passive, frightened, angry. I was always thinking 'Oh my God, I can't do that'. But during my search of over 20 years, I found that when I relearned certain responses, my life changed dramatically."
For those of us who are not yet at that stage, she is there to lead us by the hand. "When you're caught up in a constantly competitive rat race, striving for perfection, beauty, success, it's very demeaning. But you can act 'as if' to build self-esteem. If you act as if you are positive and full of confidence, you'll eventually feel as if you are."
However, it is not easy and can take a long time, she warns. This is a fact that media hypnotherapist Paul McKenna does not point out in his best-selling self-help tapes. His Supreme Self-Confidence tape assures us that "this is all you need to establish your confidence. I promise to improve your life."
Well Paul, after listening to side one on the conscious mind and then side two, when you attempt to put me in a trance that will "programme my unconscious mind for success", I did feel different: I fell asleep during my "trance" and, slumped over my computer, developed a whopping great pain in my neck that I did not have before.
To give McKenna due credit, he does say that you need to work with the tapes daily for three weeks and press your finger and thumb together 21 times in a row, imagining a moment in which you radiate confidence and saying "I AM CONFIDENT" before you can reach your goal. (What happens if you only do it 20 times, or 19, I wonder?)
But who knows? It is possible that less cynical souls will get what they want from this curiously one-dimensional approach.
But in the end, all evidence points to the fact that self-esteem is a complex business that requires a lot of work and a great deal of patience. It is not easy to direct your energy positively when you are feeling like a slug, when doing anything much more than getting out of bed is a supreme effort.
But you owe it to yourself, to everybody around you and, not least of all,the children you teach, to conquer your negativity. Your journey need not be of Californian dimensions, but coming through to the other side and being able to smile at yourself in a mirror - let alone at your headteacher in the corridor - will feel terrific.
VoiceWorks runs self-esteem workshops for corporate and other groups. Tel: Philippa Davies on
0181 749 6996
Paul McKenna's audio tape Supreme Self-Confidence, #163;10.99. Tel: 01455 852 233
Women's Therapy Centre runs groups and workshops as well as a database of women therapists.
Tel: 0171 263 6200
Dare to Connect How to create confidence, trust and loving relationships' by Susan Jeffers, #163;5.99 from Piatkus Books
Sixty Tips for Self-Esteem
by psychotherapist Lynda Field,
#163;5.99 from Element Books