Why do I always throw-up?

When ever i even have a sip of alchohal i throw up! I used to be able to just chug whatever was in front of me but now i cant rink with out barfing right away! i even try coolers and after a few , they taste fine but i still almost barf! i dont know whyyy!! t makes me really mad that i cant drink anymore cause ill jjust barf no madder what! whyy!!!!?????? some one told me it was all in my head but it defs aint cause ive tried soo hard and so many times even if it taste good. please someone have the solution!!