I Want To Let Go Of The Past And Block Obsessive Thoughts

I've always tried to deal with my problems by myself, without any help, but now it's getting to the point where my issues are affecting me every day. I am overfilled with obsessive negative thoughts, mostly about things that have already occurred. The smallest things can trigger it and it becomes a downward spiral. I replay a video in my head of the stupid things that I've done or said, how I should have acted differently, etc. All those things make me feel horrible and anxious inside. I sit in my room, refuse to come out and become extremely self-cautious for the next time I have to talk to people. Then I start self shaming myself and it becomes an infinite loop I've been living with for the last couple of years.

But recently, something else has started happening that not only affects me, but my girlfriend, who I love very much. She had a tough time growing up and in high school started going to parties and turned to alcohol, drugs and hook ups to try and escape her issues. She made new friends who were absolutely a terrible influence on her that pressured her into all those things. I fell for this girl and we started going out and have been for over 8 months now. What started happening recently is my mind started replaying images in my head of the life she used to life and it makes me feel horrible and anxious. I start seeing her with other guys and I cannot stop it. Since I told her from the start that I'm always there for her and she can tell me anything, she always told everything honestly and in full, she said it helped her get over her issues. Since she did that, I knew the guys, what they did, where they did, etc. This creates a very detailed and disturbing image that I have no way of stopping. I start seeing everything else and it makes me feel so horrible. On top of all my other issues this just absolutely cripples me and I become so anxious and uncomfortable that I just stay in my room and don't do anything. I HATE these thoughts and feelings, considering she has been an amazing girlfriend and I'm really happy that I was able to gain her trust and have these open discussions.

The smallest thing can trigger it, like a photograph of her from a couple of years ago, or running into a guy I know has at one point done something with her. I feel so embarrassed about even having these thoughts and feelings and I really need help on how to block them out. Any help would be amazing, thank you.
it14 it14
18-21, M
Jan 21, 2013