Hi! I Have A 12 Year Old Son Who Has

Hi! I have a 12 year old son who has had stomaching cramping along with alernating constipation and diarrhea. He often throws up as well, multiple times a day. He often gets very pale and clammy. He's had abdominal sonograms, an EGD and colonoscopy, and an abdominal X-ray. So far, all have come back fine (still waiting on biopsies from EGD and colonoscopy). I'm told blood work all looks good, they tested thyroid function, that came back good as well. We aren't sure what to do next. I see the vomit, I see the pale, clammy skin. School has made accommodations for him when he's not feeling well so he doesn't have to leave so it's not like he's missing school. He's tired of being asked if he likes school, yes he does. What should we do next or any thoughts?!?