But he does not blame his teachers for failing to help. He has no doubt that they would have offered him more support if it had not been for the notorious Section 28 legislation, which prohibits local authorities from promoting either homosexuality or the "acceptability of homosexuality as a pretended family relationship".
The Government is to repeal Section 28, which has caused confusion within local education authorities and their schools over how to handle the subject.
Meanwhile Tory leader William Hague appears to be rethinking his hard-line position on the Act, since sacking Shaun Woodward from his front benches after he spoke out supporting the Government's line.
John, who asked for his real name to be withheld, went to school in Mr Woodward's Witney constituency in Oxfordshire. He said: "I used to be bullied all the time. The abuse has happened throughout my life from as early as I can remember.
"One day when I was at school, in a science lesson, the teacher was out of the class and this girl shouted 'Oi, poofter'. That was the day I just went completely psycho. I went into the headteacher's office and found the deputy there.
"She was really lovely about it. We had a very good relationship. She suggested I should talk to my doctor, which I did, and he referred me to a psychologist. But the psychologist was no help.
"If I had been able to talk properly to my teacher and she had been able to put her arm around me and tell me it was all right to be different, it would have been so much easier to cope."
John's belief that Section 28 prevented his teachers from saying homosexuality was acceptable, and made it harder for them to help him, was supported by his former deputy head.
She said: "I have always felt that I wasn't able to help him in the way I really wanted to. It is perfectly natural for teachers to support their pupils when they are distressed and this should apply to all pupils, regardless of their sexuality.
"We really have been impaired by Section 28 and what it says about the acceptability of homosexuality."
John said he was predicted to get As and Bs in his GCSEs, but ended up with one A, two Cs and the rest Es. He said: "It means that, just because a few politicians are homophobic, people like me are deprived of an education - because of what happens to them at the most vulnerable time of their life."
Andrew Smith, chief secretary to the Treasury and MP for Oxford East said:
"Repealing Section 28 is a common sense measure, which will help to prevent anti-gay bullying in our schools and on our streets."