Getting drunk quicker

My boyfriend and I went to a club Friday night. I had 1.5 Sex on the Beaches and I was so drunk that I threw up 3 times that night. I felt tipsy after 1/4 of the first one. Usually I can drink WAY more than this. Has this ever happened to anyone? If so, what was the reason? The only thing that came up when I googled it was that I could be in the beginning of a pregnancy.