Its been more than 3 weeks since i masturbated and still its hard for me maintain an erection.i cannot get hard in shower and when i try to fanatasize i can get erect but nor fir lonf time just fir few seconds.it was not case before because once i had stopped masrtubation for 2 week i had got the perfrect erection hard and could maintain it fir long ,but now its not happening i dint know whats wrong please help me.i think i have lost my libido too.whats wrong?