Thank you for your query at AskTheDoctor.com
I understand your concern.
Fall in grades and lack of concentration is a common problem, which can be overcome with motivation. However, sometimes pathological problems like anemia can also cause similar problems.
I will advise you to get a blood test done and also take a multivitamin-multimineral supplement like Neurobion Forte.
Hope this was helpful,
These Q&A’s are for educational purposes and should not be relied upon as a substitute for medical advice you may receive from your physician. If you have a medical emergency, please call 911. These answers do not constitute or initiate a patient/doctor relationship.