what should i do do increase my memory power ??

Maybe mental blackout. Don't pressure your mind too much. Get enough sleep, rest and exercise. Try doing breathing exercise as this helps circulate oxygen in the body and in to your brain. As for long term increase in memory try drinking memory enhancer formula drinks. A lot of them can be found in leading supermarkets and grocery stores. Also load up on beans and nuts. They help boost memory.

Relax, have enough sleep, eat nutritious food, avoid cramming, study for 2 hours maximum a day... and lastly, have fun studying.

Don't be nervous.You had better go for an outing or travel with your family.I hope you can be better soon.