I had gastric bypass surgery in November. I don t drink enough water so i sometimes get constipated. I haven t gone in a few days. just before bed last night I started getting sharp upper abdomen pain, right side, and lower back pain. It woke me during the night so thinking it was constipation i took Milk of Magnesium. Pain woke me again but still nothing, and no gas either. This morning I drank chocolate milk because i thought it was constipation and sugar will cause dumping syndrome. I finally moved my bowels, but the pain has not subsided. My back still hurts and the abdominal pain is more focused on the upper left side of the belly button now. The pain is quite severe and i can t find any relief. i haven t taken anything and I do not have a temperature. I have eaten today, but very little. I m not sure if it might be gallstones, kidney stones or something else. Should I go to ER or wait until morning and call PCP? Pain has been almost 24 hours now