How can i get out of Pe? I have a valid reason.?

You should tell your mum how you are feeling, and hopefully she will get you some help. The school cant make you do PE if the doc says you shouldnt, or at least they should not make you do the things you cant do. The teacher should not be shouting and screaming or calling you stupid and pathetic. Tell your mum that also. The main thing to focus on is getting to the doctor and maybe talking to a counsellor or someone like that. It will take time and the school should be accommodating given that you have an illness.