Parents don't believe in my struggle with mental health

For the past year or so, ever since I had a fall out with a friend, my mental health hasn't been the best. I miss a lot of school, barely study for exams and stopped spending time on my hobbies, instead I spend most of the day on my computer despite hating myself for doing so. The only things that make me feel normal are meeting up, and playing games with my friends. I finally started the process of trying to get help for my undiagnosed ADHD or depression which my parents agreed to initially, but now I don't even know if they want to continue. A few days ago, I guess I was playing games longer than I was supposed to because when they found out they completely freaked out . Now I am no longer allowed to meet friends or play games because they believe that is the reason for my lack of focus in school. Any time I've tried opening up to them about my mental health issues they undermine it by saying that I just need to put my focus on school and get rid of my distractions as if I haven't been trying to do that for months now. My parents dont believe that I have any actual struggles and am making up all of it as an excuse for my laziness. I dont even feel safe in my own home right now considering they could start scolding me for something or the other at any point in time.