I Have Been Constipated, Nausea,stomach Pain,loss Of Appetite,bouts Of Diarrhoea

I have been constipated, nausea,stomach pain,loss of appetite,bouts of diarrhoea since early September. I can only rake a few small bites of food at a time. Today it feels as if intestines are backing up into stomach. I have only had half a piece of toast with peanut butter and half a cup of soup today, but stomach feels really full. I also drink water and gator aid. I do have fiber, celiac disease, barriers esophigus.