Suddenly cant drink anymore? Any help

Heya, ive always been a social drinker, dont rlly like the taste but would always drink a lot for nights out etc. nearing the end of uni now and suddenly i cant drink anymore… have i broken my ability to? It makes me instantly sick now after a few sips, i vomit faster, get drunk faster and have had a load of embarrassing drunk moments recently. I used to be able to drink a whole bottle of vodka and make it through the night fine, now two ciders in im done, got a headache and tap out. Idk whats wrong. Am i getting old or something