This is my first post here. I am getting desperate. My apologies in advance for the long post.

Up until December 2007 I had never had any erectile issues and could have an erection several times a day as healthy male in their mid to late 30's normally could.

My girlfriend and I were having sex in December 2007 and my penis incurred some trauma while she was on top of me.  I heard the ‘snapping' sound in my penis when the trauma occurred.  I immediately lost my erection when the trauma occurred and thought I would regain my erection strength within a few days.  This did not happen so I sought help from others.  

In early 2008 I went to the Boston Medical Group (BMG) and they assured me I would be fine. Just to avoid sex for a few weeks. They gave me 10mg of Cialis to take. This helped my confidence for two weeks and I was able to perform when we started having sex again, however still not achieving a 'full' erection like I could pre-trauma.

I figured I would take Cialis for 1 month as recommended to ensure I was back to normal however my erection failed a few weeks after that even after I took Cialis. I went back to the doctor (BMG) and he gave me 20mg of Cialis. Still I was not achieving full erections and having hit or miss episodes with intercourse.  BMG then recommended the injections which I was not ready for. 

I then went to the urologist who could not find anything wrong. He asked if my penis had gotten purple in color and very swollen when the trauma happened (I was swollen but the color did not change.) He mentioned that as I get older I may detect an increase in the curvature of my penis which could be corrected. This may occur at the site which my penis was bent during the trauma. He said this may occur when I am in my 50's or 60's. He did not find any hard nodule at the trauma site.

He gave me Viagra but then suggested that I get a blood test to check my testosterone levels and blood sugar.  I did this and everything came back normal (testosterone serum 463 ng/dl).  The Viagra helps sometimes but sometimes I cannot reach orgasm when I take Viagra.  Also, my erection is still not as rigid with meds, only semi erect, enough to penetrate but I really don't feel that much.  The sensitivity has diminished in my penis. 

I also had a penile Doppler test and the results came back normal.  (right side: 72.3 psyst cm/sec, left side: 33.8 psyst cm/sec.)  I was sure I had a leak in either my artery or vein but I'm not sure if the Doppler results would negate this feeling.  The urologist did not return my follow up calls in a timely manner so this was also frustrating.

Since the trauma occurred I feel a severe loss of libido and it is beginning to affect my psychologically.  I feel that I am starting to avoid intimacy. My girlfriend has been very supportive but she also feels guilty for ‘causing' this condition. 

The added complication is that my dad is a local urologist but I feel too ashamed to tell him what I am going through.

So to recap...
1. No structural damage to my penis upon exam by the urologist.
2. Blood flow to my penis is above normal according to the doppler test
3. No diabetes or high blood sugar
4. My testosterone levels are normal.
5. I do not get morning erections like I used to pre-trauma. I sometimes can feel very slight morning 'wood' around 5-6am but never fully erect.
6. Viagra (half tablet) helps, sometimes for an extended period...sometimes I feel ok but not great for 3+ days. Sometimes Viagra does not help at all which I don't understand. I can have sex without any meds sometimes as well.
7. My confidence is shot and sometimes I make excuses to avoid intimacy.

8. My orgasms have improved since immediately after the trauma, but still not earth shaking as before the trauma.
9. I had gained weight this year (about 6-7 pounds since the trauma and about 10 pounds above my ideal weight) and the urologist told me that weight gain can affect an erection; however I find it hard to believe 7 extra pounds can make this much of a difference. 

I am wondering if some blood vessels or nerves could have been damaged and if I will ever regain my firmness. Even when I masturbate my erection does not feel as firm and without constant stimulation I go soft.  As I mentioned, I am not getting full erections in the morning anymore like I was pre trauma and sometimes I do not get even partial nocturnal erections

I've started researching ED on the internet and I have another appointment with a new urologist mid April 2009. I've been doing research on what tests can be done. Can anyone tell me the difference between the following:

1. Penile Biothesiometry
2. Ultrasonography
3. Color Doppler Sonography
4. Color Duplex Ultrasound

5. Nocturnal tests to detect erections

Are these the same or do they measure different things? 

Any advice or suggestions would be greatly appreciated. 

And I am sorry for the long post.   

Thank you.