This happens to me quite a lot, and it's often about social situations and people I've screwed up with in the past. The hurt from things I've done and regretted is just so immense that it is so hard to get my mind off of it.
With people that I've realized I obviously dislike, the situations concerning them don't matter...but when it comes to people I admire and have a positive history with, it just affects me in a really encompassing way where I just can't seem to think about anything else.
Luckily, recently I have found solutions. A couple weeks ago, I was obsessing over this girl I used to hang out with and her group of friends to the point where I had a meltdown and I was unable to concentrate on anything., I blocked them out by becoming busy. I've been really focusing on school, getting errands done throughout the day, getting a job and volunteer work in place, and filling up my schedule...anything to keep me from obsessing. I also have to look at the thought constructively...what can I realistically do about it? I decided to get this girl's number from another friend and am going to call her when I'm ready to.
I'd bet that by replacing one obsession with a more productive one (in my case, being organized and overall successful), it would be easier to get rid of preoccupying thoughts.
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Given a “tentative” diagnosis as a child as I needed services at school for what was later correctly discovered to be a major anxiety disorder.
This misdiagnosis caused me significant stress, which lessened upon finding out the truth about myself from my current and past long-term therapists - that I am an anxious and highly sensitive person but do not have an autism spectrum disorder.
My diagnoses - social anxiety disorder and obsessive-compulsive disorder.
I’m no longer involved with the ASD world.