There isn't sufficient information to suggest a specific diagnosis. It is possible that you could have hyperacidity causing gastritis which is causing this. You could also have vitamin deficiency of Vitamin D and B12 due to improper diet. The following steps may help: - 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 (30-45 mins/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/tai-chi.

Loss of appetite could be due to acidity or some other organ related disease like kidney, liver, heart, intestine... Most cases are due to acidity... which can manifest as belching, heaviness, burning sensation, nausea. Likewise tiredness can be due to acidity, organ related diseases, low Haemoglobin, low vitamin d and B 12, thyroid disease.