Hi..im 20 Years Old(male).im Having Prone Masturbate Habit From My

hi..im 20 years old(male).im having prone masturbate habit from my childhood,when i was about 12 years old.day by day i became addicted to it.i tried a lot of times to avoid it but i failed because im so much addicted.i spend a lot of time on my bed.sometimes i did it 5/6 or 7 times in a day!and i tried like no sperm could come out.i did it on my bed.i still doing it.now im about 52 kg.height 5.6 feet.so much skinny.my wrist and forearms are so skinny like my childhood.i think i damaged my body a lot.my questions are what kind of damage i did to myself,is there any way to improve my skinny body and how?and how to avoid prone mastuebation...im in so much depression about my health..sorry for my bad english