No idea what's wrong :/

For the past few weeks, I've been feeling on and off nauseous. At first it was just once or twice a week in the afternoon, but now it has become pretty much every time I eat something. I never actually get physically sick, I just feel very very ill for ten to twenty minutes after eating. I have no idea what is causing this. I went to the doctors yesterday and they told me my stomach was out of place, but they fixed it and said it should be better, but this feeling has continued. Everyone's first question is if I'm pregnant, and I am 100% certain that I'm not, so I have no idea what's up with me. I just hate to eat now because I know I'll feel sick. Ughhh.