Hunger, diarrhea, belching... it's freaking me out

I have a long history of digestive issues. But recently it's been scaring me. I feel hungry, incredibly hungry. I eat but have to stop not because I'm full, but because I feel nauseous. Doesn't matter what it is I'm eating. And within half an hour, if not less, I have usually at least two episodes of diarrhea. Sometimes the food is completely undigested. Between episodes I feel nauseous until it happens again. I feel the need to belch on a regular basis.I also wake up in the morning with my entire lower abdomen hurting.

Like I said, I've had problems in the past (which also went pretty much undiagnosed, but they just went away) but this is really scary. Any help would be so great. I'm worrying myself into fits here.