Sir .i am 20 years male .an I am studying mbbs 3rd year .i had a habit of masturbation I do 3 times a day .last year my penis is a big size after erection now I am feeling like my penis decreases in size and strength .and 4 days onwards I had vibrations in my testicles .why they were vibrating like that .and I had a fear about my penis .why I am losing strength in penis .will it impact badly on my sex life .suggest me a way to have a previous strength and size of my penis.