hi i'm 25 years old single men. i'm masturbating for last 10 years but suddenly i lost my erection for last 2 weeks my penis is not getting hard, if i play with it it's getting hard only for some time but in the sleep when i woke in middle of night my penis is hard and in some situations it is getting hard while seeing porn a little bit erect but not as usually erection can any please help this problem