Could be stomach flu. That usualy gives you the dry heaves. If it was somthing you ate you would have diarrhea along with vomiting. Either way drink lots of fluids. many small sips is best.
Oh gosh - you poor thing - don"t tell me you have the same nasty stomach virus I had last week - for 2 days I dind't know whether I was coming of going it actually (sorry guys) came out of both ends.
Try and keep hydrated as muchas you can.
The only good thing is that I lost about 7 lbs in the process!