I don't know anymore

The thing is my mental health has spiraled out of control. I lost a huge part of my summer to it because I couldn't will myself out of bed to do anything for the past month. Long story short I've known I've had problems since like 4th grade, I'm going into my senior year of high school next week, the last 2 school years it's gotten worse than ever before (self harm and abusing sleeping pills happened a couple of times a week), and now I don't even know how to hide it or deal with it without doing something really stupid.

The last few months have kind of just destroyed me. First I was stuck in bed with an injury I wasn't sure I'd ever 100% come back from, then my family life is falling apart with my grandmother suffering from dementia and I have like 0 contact with the part of my family I was counting on not hating me after I come out. Now just in the last week I lost 2 pets who were really important to me and a third might just be dying with nothing I can do to help her.

I haven't gotten sleep in the past week because of symptoms I'm afraid might be a stomach ulcer from stress. My girlfriend can tell I'm falling apart and I hate seeing her so worried. I just don't know what to do anymore. I can't even go see a therapist because my parents don't believe in mental health.