I’m really scared to turn 18

hI. sorry in advance for the long post. I turn 18 in a couple of months and I am so scared, I feel so behind in life because I haven’t gone to school since I was 14, I have an anxiety disorder as well as pretty bad OCD, and I’m starting to think i might have depression as well. anyway I’m just so scared that I’m going to be like this forever, I mean I have always heard about people who find comfort in there mental disorders but never thought I would be one of them but I guess I have lived with them in so many years they have become the norm for me. anyways a couple weeks ago I went to the psychiatrist we have here in dk for people under 18 and she said something about me turning 18 and that petrified me. I haven’t been able to do any of the stuff I normally do and love, I love reading wether that be romance or mystery thrillers or fan fics but haven’t been able to because I feel childish and like nobody else does it, I have also not been able to watch TV shows because I’m either watching something about teenagers and all i can think about is that’s what I’m supposed to be like, or something about adults and then all i can think about is that’s supposed to be me in a few years,I used to love watching cartoons but can’t watch them cause I feel childish, haven’t been able to color in my coloring books either because it feels childish. i don’t know what to do if anybody else have felt like this please give me advice cause I’m at the edge here I’m crying every night and feel so useless and like a burden, sorry again for the extremely long rant.

mif you’re going to say something negative please don’t I already have those thought every day:)