Hi Bactor,
We certainly can't diagnose you, as you know. We can only offer our perspective and opinions, ideas.
Have you ever seen that movie, "Anger Management" with Adam Sandler? Very funny movie! A lot of what you said seems to fall into that category. Did you work with a T when you were a young boy, being bullied? Read any books or belong to any support groups to help you work through those deep emotions of pain and humiliation?
I know that you aren't real comfortable with the idea of seeing a T at this point in your life, but it really does sound as though you need to find healthy ways to work through these deep emotions so you aren't always on the brink of losing control. It's good that you aren't attacking others when these intense emotions strike you ~ but I can guarantee that you scare the hell out of your gf when you have your outbursts! That's not good.
http://www.mayoclinic.com/health/ang...gement/MH00102
Do try looking at the attached website for tips on managing your anger in a healthy way, and also try looking into local support groups. Just meeting with others who struggle with similar problems can be a big relief! I wish you the best ~ good luck to you!