I've had upset/nauseated stomach for the past three weeks. had a haemotology report, stool sample, and urine sample come back clear. what is wrong?!

Much to talk about.: First do you take too much caffeine. Are you drinking and not telling anyone. ARe you taking some sort of supplement from over the counter. If none of these are true , it could be reflux which is a little unusual for your age. The next consideration might be the use of meds like advil (ibuprofen). See your doc for further need of investigation. Is this upset stomach or could it be lower in abd. Pregnant?