The causes for the symptoms as mentioned in your post can be:
1. Any fluctuation in the blood pressure & blood sugar levels.
2. Inadequate hydration status & electrolyte balance of the body.
3. Deficiencies of certain nutrients like Iron, Vitamin B 12, Folic acid
, etc. which interferes with blood formation.
& metabolic causes.
5. Stress, inadequate sleep, etc.
Investigations like complete blood count
, estimation of blood pressure & blood sugar levels will be helpful to rule out any pathological cause for the symptoms.
And it is also needed that you take certain precautions regarding your diet & lifestyle, such as:
1. Take soft, plain, non-spicy foods
2. Drink lots of water to maintain adequate hydration
3. Avoid fast foods & gas producing food products like cabbage, etc.
4. Avoid smoking
5. Keep away stress..think positive.
6. Exercise regularly & practice meditation
Wishing you a Good Health.
Thanks & take care.