mastebation. I am too depressed for what i have did.

i am doing masturbation from last 8 year, earlier i used to do it 7 time in a week almost per day,now i feel pain in left side of testes also my erection time during masturbation is almost less than 1 minute, i am unmarried and aged 21 year. I am too depressed for what i have did. plz help me