Is it the nausea or the pain which is causing you to stay away from foods? Are you drinking liquids?

This happened to me this summer, and it got so bad that i couldn't eat anything other than drink water and take vitamins. I went to the doctor and found out that I had a form of acid reflux. It started out as being nausea and progressed to the more common forms of acid reflux like the heartburns and nausea. They gave me Prilosec (OTC) and i cleared up within a week. It took me awhile to eat certain foods, and still avoid a lot of the triggering ones. But pop tarts were and still are a big issue for me. My doctor said it's the milk sugar in pop tarts and in thinks like cookies and birthday cake, which i also avoid. You may be slightly lactose intolerant, too...and thus should avoid those types of foods or buy some lactaid pills to take before you eat such foods to help your body handle the milk sugars.

Stress and/or anxiety can also be a cause of the sudden onset. Mine was stress upon entering college and long work days and work outs. So i basically took it easy and it made everything so much better