my stomach hurt after drinking alc

Hey guys help me ,everytime i drink alc my stomach hurts sm just like im on my period even worse sometimes. Usually i drink vodka and i mix it with cola cola . The last time i decided to drink wiskey and see if there is any difference but no sadly. I mixed it with coca cola again. The same thing happened . I prefer to drink cause i feel more relaxed but this shit happens everytime i go to the club. i have no problem drinking coke alone . I also ate food before drinking. Pls if someone knows why this happens and how to prevent it share w me .