My stomach gets upset almost every time after alcohol, what should I do?

So I have a problem. It seems like I can’t drink too much because my stomach gets agitated and I have a feeling of throwing up even tho I didn’t drink that much. And like I said, this isn’t because of 6 or more beers, even 2 beers can cause that. And day later I feel my stomach is more sensitive. That’s why I in general avoid alcohol however ofcourse I’m going to drink something at the party or going out. Is there a way to deal with this? Does anyone have a same problem?