19 year old possible impotence/low sex drive

[brighton1904]

I am a 19 year old male with a lower sex drive than before and I have had difficulties obtaining and maintaining an erection during oral sex and intercourse.  

I have looked up the possible causes, so here are some details about me. I am physically active and in good shape, I smoke marijuana on at least a weekly basis but I have been cutting down alot recently.  Additionally, I use a hookah occasionally and have some difficulty sleeping and feeling well rested.

Anyhow, when I masturbate (about once a week, much less than I used to) I can maintain an erection and ejaculate but when I am actually with a girl, I get an erection but lose it and am unable to penetrate.  Now, I know that marijuana, tobacco, and sleep problems can cause difficulties, but I have been recently attending to them and I have not seen improvement.  What sort of problems may I have

[death_ninja91]

I have the simmiler problems,cept i don;t smoke,i don;t do smoke weed only every other 2 mths but i do have a problem sleeping Also my erection only last like at least 30 minutes to half an hour

[SixStringer]

For general health reasons, I would recommend stopping the marijuana and hookah 100%, especially if they are still affecting your sleep.  Sleep is very necessary, as it is a time when the body repairs itself.  The weekly masturbation should not be a problem, but the ED you've been experiencing with your girlfriend might be influenced by the kind of sexual fantasies which excite you when you are alone, if you are doing something else with her.  Try doing more foreplay and make things as enjoyable as you can without concentrating on performance.  In time, your situation should improve.