Erectile dysfuntion in teenage. Help!!

Hye, i am a 19 year old guy. I have been excersising in the gym since a year and a half. I could get damn good erections earlier (before august 2008), until i joined my college. After i joined my college, I didnt have breakfast those days and didnt eat anything in the college the whole day, and i was heading straight to the gym and forcing myself there. (in short i didnt eat anything for 12 hours everyday and worked out like hell in the gym.) The only time i ate was after the gym. i.e. i was eating only one meal a day with damn forcing workout. I dont know what happened after a month or so, i was unable to get any erections. i researched a lot but nothing helped me. i somehow arranged to get food at my college hours, and after another month or so i was able to get erections, but very, very weak. I dont get hard, i get only semi erections, also, which do not last for long. Earlier i used to get uncontrollable erections, i dont know what happened now!!

I am sure it is not psychological Erectile dysfunction. Maybe it is due to lower levels of testosterone or due to some damn neurological disorder.
I am not on drugs, alcohol or smoking, i am not obese, i workout regularly, i am not diabetic.

Please tell me that should i take any aromatase inhibitor like 4-Androstene-3,6,17-trione. Would it help?
Also tell me if tribulus terrstris or catuaba bark would help.
If any of the above medicines would help please tell me the company name which manufactures it and where can i get it from.

Waiting for a reply. Please help me out.