Severe sexual problems, advise? thoughts?

So, I am at a very low point in my life right now, and it seems that nobody gives a ****. I am a 20 year old male, and a junior in college. About 2 years ago, I was having some severe depression problems (always been prone to depression and anxiety) because of a variety of factors, mainly the break up of my relationship of 4 years. I went to a psychiatrist and she promptly put me on Lexapro, which made me feel some better, but caused me lots of nasty sexual side effects, including trouble getting and maintaining an erection, loss of libido, and even trouble urinating. I quickly got off Lexapro, but my erectile dysfunction never got better. I had a new girlfriend at the time, and it was very frustrating for both of us when I was unable to achieve an erection with her, and after a year of dating, we broke up. I now have a new girlfriend, even though I was reluctant to get into a new relationship with all of my problems, but I have fallen for her and care for her deeply. I have been to several doctors, and 2 urologists, and they tell me I am completely normal and this is all in my head. I was given Cialis, and it helps, but I am still not achieving erections like I used to, and I still have no sex drive. I had my first failed sex attempt the other night with my new gf, and while she said it was ok, I don't think it is. This is ruining my life, because I cannot stop a subconscious fear that is ruining my life. I don't know what to do, and I am about to blow another relationship with a great girl. I am afraid that I will never find companionship with anyone that will last, because I am unable to have sex. I know this is not the most important part of a relationship, but still, everyone needs sex. I am afraid that I will be lonely forever, never having a family and being alone, because I don't think my condition is treatable. I have become a slave to a subconscious mental problem. I am really down right now, and my relationship is crumbling, and I don't know what to do. I feel like I am the only person that has ever gone through this. Why can I not be normal and happy? I like to think I am a good person, and I try my best in relationships, being a caring and loving person, I am just having trouble physically loving someone. Has anyone else gone through this? Any advise or thoughts?