If you don't feel comfortable asking your parents to get you into therapy, I wonder if there's a school counselor you can talk to? It sounds like more than just depression to me, but of course I'm no expert on this. I'm unsure what else to suggest it may be, but you could do some research of your own and see if anything fits for you. It will take a bit of self awareness and being able to be honest with yourself. If you find something that fits you well then you can look into self-help measures related to that problem and when you turn 18 can sign yourself up for therapy.

I felt similar regarding trusting people and feeling emotions properly at that age. I was also pretty mean, but I didn't intend to be, I just went too far with bluntness or playing around too much.