I hate my life..

I really don't know what to do. I've struggled with mental illness (anxiety and depression) for the majority of my life and I don't know how much longer I can take it. When things seem like they're getting better, they just crash down again. I hate who I am. I don't have any close friends, I'm socially anxious, and I'm painfully shy. I'm sick of being so lonely and it's the most frustrating thing ever because I want more than anything to have friends like I used to. I break down every night (I wish I was exaggerating) and normally end up crying myself to sleep. I can't really tell anyone because my parents get sick of how I'm constantly like this and I don't blame them. I go to a therapist but he isn't helpful. I'm a teenager and these are supposed to be the best years of my life but they're the complete opposite. Has anyone else on here been where I am? Any advice would be appreciated😞❤️