impotence at age 20

I am a 20 year old male who has had no hard erections or morning wood for the past year. I could barely have sex with the help of v1agra during this period, but now v1agra has no effect what so ever. Now I dont even have the ability to spank the monkey and rarely think about sex. Prior to being age 20, I had what I believe a raging sex drive, I would connstantly think about sex and spank the monkeyd 3-5 times a day every day. I have seen many doctors and one urologists and they all say it is in my head, meaning psychological. I had blood tests, and they say everything is normal with my testosterone being in the normal to high range. This condition has ended many reltionships and without wellbutrin, I am near suicidal and suicide is constantly on my mine without wellbutrin. My question is what could cause this? Is there any cure? Or im I stuck with this for life? I barely have enough motivation to make it through the day. Please help and offer any advice.