Thank you for choosing Health care magic as a platform to gain answers to your queries. By losing sperm, I assume you mean masturbation
or Wet dreams. There are lots of myths regaridng masturbation and wet dreams and one of them is that the sperm has lot of mineral / iron content which when lost in large amounts like during wet dreams or masturbation leads to physical weakenss or impotency. But these are only myths. Wet dreams are nature's ways of maintaing the semen account in the body and masturbation is a healthy was of satisfying one's sexual needs, especially at your age when you cant play unsafe and cannot commit to partner for life.
But what you have to keep in mind is anything in excess is bad for health...food, tv, sleep or masturbation. Main disadvantage is preoccupation with sexual thoughts and activity which would distract you from Studying the main task for you currently...and also would lead to such anxities as you have now and have posted this question. The solution is maintaining a balance in your life wherein your are able to prioritise your needs and devote appropriate time to them accordingly.
Let me know if you need any other assisstance.
All the best for your future and dont worry...
RCI Reg no A-12344