Hi ! Good afternoon. I am Dr Shareef answering your query. If you eat from outside, it could be due to some intestinal infection. If I were your doctor, I would advise against it, and go for a stool test of yours for ova and cyst and treat it if positive. This should relieve your symptoms possibly due to collitis. However, when you go to your doctor, he would physically examine your abdomen, and would make sure to rule out inflammation of appendix, an organ inside your abdomen on the right lower side. If need be, he might also advise you for an ultrasound, an painless imaging device of your abdomen by which intra abdominal organs could be assessed easily. I could advise you of some medicines only after all these investigations have taken place and the reports are ready. I hope this information would help you in discussing with your family physician/treating doctor in further management of your problem. Please do not hesitate to ask in case of any further doubts. Thanks for choosing health care magic to clear doubts on your health problems. I wish you an early recovery. Dr Shareef.