I just threw up all of sudden...why?

I was on the computer and I was feeling fine, then I feel sick, I get up to go to the bathroom but i fell down and threw up (foamy white and liquid yellow) 3 times. I got up and took my temp...98.7 perfect temp. It's been about 4 hours since then and I feel ok. I'm on my period so im not pregnat. Whats going on?