counterfeit/fake vodka

i (16F) have been drinking vodka from a local shop (literally the only place that serves me around here) and i’m starting to get concerned that the vodka is counterfeit or fake or something like that.

the first time i tried it, i burst into tears and couldn’t stop crying, i found it extremely hard to hold my head up and i got incredibly aggressive.

the second time i drank it, i had 1 desperados beforehand and had about a quarter of the 35cl bottle before throwing up everywhere. the hangovers from it last for days and i always end up blacking out afterwards. i’m 45kg and 4’11 so might be why but i’m a little frightened… any help?