I feel hungover but I barely drank?

I went to a party last night and I literally only had a few sips of mike's hard lemonade and after the party I realized I had an awful headache and I still kinda have it. I tried drinking Gatorade but it didn't really help and I just feel pretty shitty. I know I'm obviously not actually hungover but why do I feel like this and how can I feel better?