13 and I need help

I’m 13 and a girl, and i think I’ve got a mental illness of some kind. I have random down days, where I just don’t talk to anyone and go home and watch anime and sleep. I tried to make myself throw up 6 times in the last three weeks, however I dont seem to have a gag reflex as I put my fingers as far down my throat as I could and I choked a bit but didn’t throw up. My parents call me worthless or a waste of space if I do something wrong, which makes me feel really down and I cry a lot from this and my friend notices sometimes as she knows what they’re like.I get random headaches, have trouble sleeping, flinch and panic if someone like touches me or hug me, I get a stammer when I’m unhappy sometimes, and I feel alone all the time, even if I’m with people.i feel fat and ugly all the time.I think about suicide, not seriously, just like what would people think if I did die. I think about the people that have wished me dead, and whether they’d be upset, or blame themselves, or just say I did it for more attention.People don’t really like me, but I feel like it’s my fault because if I find out they don’t I just don’t talk to them. I self harmed but now I’m clean. Despite all of this my parents don’t believe in mental illness and think I’m doing it for attention, what do I do before this gets worse, and does anyone have any ideas what could be wrong with me???