i always think venting will help but it never does, i moved to a different state and shut out everything that was bad for me and made me a shell of a person.
I rarely thought about things that have happened, something id have internal dialogue but it would be whatever but a couple weeks ago my friend and i got drunk and had an deep conversation about a situation that happened years ago and i honestly thought i was over- but ever since then ive compulsively thought about it all day every day, i try my hardest to switch my brain away from it but it trails back in and sometimes i dont even realize until i tune in and im in mid argument with the person. 
Its absolute torture, i cant even escape it in my dreams. ever since i could remember ive done this with almost everything that has mildly to traumatically rattled me, no matter how much i try to grow if something sets me off i will make myself suffer until my mental state is right back in the same position.
I always thought i needed therapy but now im almost convinced shoving my feelings down is better, it was so much easier acting like it never happened.