Depression and Dr's

Hi, I just joined. I'm hoping to get some advice and guidance with my situation. I have autism, I was diagnosed nearly two years ago now. My family took it ok. Dad doesn't really believe it, I feel he feels I'm just lazy and don't try hard enough. Mum is supportive and so is my brothers but mum doesn't trust me, she keeps searching my room and tonight she read my diary where I wrote about my self harming and feeling like I want to die sometimes and now she's told me tomorrow she's calling the Dr. I've tried telling her I'm fine, not to worry because the harming is only minor which it is and my suicidal thoughts are just thoughts. But she isn't listening to me! 

I really don't want to see a Dr again. I have severe medical phobias and even talk of a Dr let alone seeing and talking to one makes my chest tight and I feel sick. If I have to see one I'll end up having a meltdown and then burn out after. I've been there before and I really don't want that to happen again.

How can I help convince my mum? I tried talking to dad but he said best listen to mum. It's not fair. They can't possibly understand what all this does to me. It causes anxiety and triggers my autism in to overload. I'm annoyed that mum went in to my room and read my diary, I don't invade her private space.