im 16 and just started collage

i feel anxious at the slightest thing and become actualy terrified what people will thing of me and as a coping mecanism i grind my teeth but then i get a fear of them falling out lately i have had no interset in food and i can't seem to concentrate in my lessons in collage i almost feel like a different person and i have really strage thoughts im my dreams i feel exhausted and have no energy im really scared that i might be kicked out of collage and i have to fake emotion around my friends as i don't seem to be able to control my emotions at all i just feel so low sorry this is so long but i just really want to know whats wrong im so scared i don't want to behave/feel like this anymore

thanks x