I can't help myself and everyone else

(TW-mentions of ED,Self Harm, and suicide).
I can't do this. I can't save myself, I was so proud of myself because I haven't Self harmed in about 3 weeks! But I got into a relationship and she is very insecure and won't eat for days on end. I am constantly begging her to eat. I can't keep up with both of our health considering that I barely can care for myself. So I fell back into self harm tonight and I'm shaking. I want to cry but I'm honestly numb. I also took an autistic test because I had heard about it and I felt like I related to it and it scared me. Instead of supporting me my cousin laughed at me, I ended up with a high score but it could just be that I'm socially awkward. Autism shares ALOT of symptoms with other things.