I suffer from a problem in maintenance of my erection a period ago i m 28 years old male ..not married ..not smoker or alcoholic ...i had sex since i was 21 and it was so normal with different partners ..then i stopped having sex when i was 25 for 2 years ..i was masturbating once daily and then last year i had sex again but i felt prb occured many times that i fail to maintain my erection hard ..sometimes i lose my erection before intercourse..and full erection occurs for a very short time i made hormonal labs and the results were F.S.H =1.2 ( normal range 0.95 to11.95 ) L.H = 2.04 ( normal range 1.14 to 8.75 ) Estradiol = 18 ( normal range up to 52 ) prolactin = 15 ( normal range 2.1 to 17.7 ) Testosterone = 1.44 ( normal range 1.3 to 7.7 ) free Testosterone = 5.0 ( normal range 4.3 to 30.4 ) i dun know how to get over this prb and if it serious ? and do i need more investigations ?