advice needed please.❤️

Basically I was in a car crash in August and it has affected me really badly. I now have Ptsd although I'm good at hiding it, I struggle most days. I don't sleep and it has made me really depressed. I am home for Christmas for university. Uni isn't going the best because I had trouble start as I was just getting walking again so didn't make friends like I expected. The major dilemma is that me and my mother are arguing so much. She doesn't understand ns she just says that I should get over it. Even with it being Christmas day she told me I ruin everything. She said it's all in my head. I really don't want to speak to her because she just doesn't understand. I guess no one can but I don't know what to do. I had a bit of therapy but it made no difference. Me and my mum used to be super close before the accident but after it I think we have grown apart and it's hurting me bad. She was like my best friend and now I can't even talk to her without being told that I'm mardy or need to get over it. Your advice would be greatly appreciated! Thank you for taking your time to read this. X