When i eat something with to much sugar or to hot, i get stomach ache. i can't digest big meals or lay down right after i eat. after meal i feel tired?

Try Antacid: Try one of the over the counter antacid before eating. If the symptoms persist or get worse you should see your doctor and get checked.

Gastroenterologist: These symptoms should not be ignored and I feel warrant an evaluation by a gastroenterologist. Appropriate tests will be done in order to make a diagnosis. You will get proper treatment and dietary advice.