You need not to worry.Masturbation
is a normal natural act. You should stop feeling guilty for this. It has nothing to do with your weakness.
Its in your mind by reading irrelevant posts on net that it causes weakness, so your getting/feeling week.
Its absolutely normal at your age.
Stop indulging your self in reading irrelevant heath queries answered by unqualified people.
Remember, Excess of every thing is Bad.. What yours in not an excess.
Dr Anshul, M.D.