Erectile Disfunction - Heres my scenario, somebody please help me!

Okay heres the scenario,

I'm currently 16 years of age. After going out with my ex girlfriend for 4 and a half months we finally had sex, but what I didn't know was this was going to ruin my reputation, confidence and self-esteem forever. I lasted under 2 minutes with her. About 5 months later, 3 months after we broke up I heard a rumour going around her school about me. This was easily the most embarrassing thing I've ever had to have gone through, even my mates have givin' me crap in front of others. Since then whenever my mates have said 'hey come out with a girl with me shes bringing a girl' I would make up an excuse because I can't bear whats already happened to occur again - I have totally lost what was once a fair bit of self confidence.

After reading up information about Erectile Disfunction it seems to be either physiological or phychological. I'm very confused as to what I exactly have. My questions are:

a) How do I know if its physiological or physchological?

b) I'm 16, who can I talk to to solve the issue? (I feel very uncomfortable talking to anyone I know personally.)

c) How should my diet be? What liquids should I be drinking/not be drinking and what foods should I been eating/not be eating?

d) How do I boost my sex drive? Foods? Liquods? What shouldn't I been consuming?

Sorry that this has been a big post but I felt I needed to explain exactly how I feel, as alot of you know ED is not a laughing matter.

Thanks in advance,

Robo