In fear of a bad reference
A: You are not on your own in feeling overwhelmed by the responsibility for your students' education. But I get a sense that you are far from being an ineffective teacher, and I'm sure your pupils will achieve well. If you have worries, share them with your pupils - and get some ideas from your induction tutor and other colleagues.
Everyone in your position has concerns - that's only natural if you're an NQT. As for the one-year contract, ask your head whether there is a chance that the job will be made permanent. That is the procedure in many schools.
And if you apply elsewhere, don't worry unduly about references. Managers don't usually write negative comments, and references are usually seen as only part of the full picture.