Struggling with my mental health and I’m to needy with my boyfriend

Hi my name is Rachel and I have Asperger’s I am really having a hard time at the moment. My mum died 2 years ago and my dad has met someone else and he moved to Scotland to live with her and they are getting married. My mental health has plummeted and i have reached rock bottom. I am dating a guy who also has Asperger and most of the time it’s amazing there a real spark there and I absolutely adore him. My mental health is so bad it has put a huge strain on our relationship and we have been arguing like cat and dog. I try to go to him for comfort but he can’t always provide it and then I get desperate and needy. I really don’t know how to break this I just want to be happy again I just want to pass university get a good job with children with autism but I’m terrified I’m going to fail.