A more detailed history including any other symptoms like fever or pain anywhere in the body needs to be known. Few investigations will be required to rule out infectious causes and any deficiency. Till then you can take a painkiller SOS and antiemetics for symptomatic relief.

It is likely that you have gastiritis. You may require antacids. The following changes may help in handling the situation: - Don't skip meals, you may not feel like eating but in such conditions you should have the reduced amount in frequent intervals(i.e. 3 square meals broken down to 5 or 6 as you can tolerate) and slowly increase as you get better. - Reduce/ Avoid spicy,fried, fatty, junk and oily food - Avoid/ Limit drinking coffee, tea and carbonated drinks to once a day - Exercise regularly (minimum 30-45mins per day) - Increase daily intake of water to 3 liters - Avoid/Stop smoking and drinking if you have the habit - Reduce stress through methods such as yoga/meditation.