ok im 17 and recently i have got myself a girlfriend somone that i care about alot but when i masturbate and when she plays with my penis it takes awhile to go up like 5 min and if i stop playing with it when its hard it goes down quite fast.

this problem started not that long ago i used to wake up in morn with a hard i used to get it up easy and take awhile to get it down.

i can still have sex because once its up its usally quite easy to keep up

so does anyone have any clues about what the problem could be this problem started about a month ago and is bugging me alot and making me worried.