Why do I get sick so easily?

About two months ago I got drunk for the first time, all out with blackout and vomiting. Before this I would have a drink every now and then, and no problems. But since that day, even a sip of alcohol has me feeling sick. One shot of previously my favorite drink has me gagging. I’ve tried new drinks, thinking that maybe it’s just the drink making me sick now, but same thing. Any alcoholic drink has me feeling sick after just one sip now. Why is this, and is there any way to make it stop?