Thanks for your query.Based on the facts that you have posted it appears that you have problem of getting night emission..This is not abnormal at all it is very common to get emission at the age of adolescence and it is not harmful to any system in the body.
The weakness that you have may be due to some other reason.
Please ensure to take high protein diet rich in vitamins
Do moderate exercise so that you get sound sleep .
There is no need to take any medicine it will get resolved of its own over a period of time.