Im an 18 year old male and my gf and i have sex at least 3 times a week and we do it more than once when we do it like i usually get soft after but then get hard with in 5 minutes or i stay hard and we do it again. but lately i get soft and cant get hard again until like 20 minutes or more. the other day i almost didnt get hard when we where about to have sex. this never use to happen. shes is really hot with a nice body. does anyone know its wrong???