I like to think of it more as a trait a coping mechanism sometimes to keep me in line and not let me repeat past mistakes or make stupid choices. it is annoying though when it gets out of hand and can keep me up at night or leave me without some thing that i may need because i have rationalized why i don't need it. i take a walk in the woods then and think only about whats around me the calm and quiet center me.
Just start believing that things really aren't so 'you' orientated. People probably didn't do a certain thing to get at you, or they are staring at you, laughing at you, whatever. I usually get the feeling over thinkers are mostly under-confident people. And by God, do not over think what I have just said.
Im a thinker too, it could be hard sometimes cos your thinking a million things at the same time at one point i become an insomniac and was always absent minded. But then alot of stuff made sense and i get alot of subjects to talk about. You just gotta figure out how to control overthinking. Thinkers are not under-confident.
Lol I'm very absent-minded but I love it. I don't stress about a lot of the daily crap other people stress about. I usually have too much in my head at one time to think about reality.. and now I have to go do my readings for Shakespeare.. bummer.. I wish I had some pot. Imagine Shakespeare while high..? I've done Coleridge and it was amazing; I was transported into the poem (if anyone's ever read Kubla Khan). Really great experience. Coleridge was--of course--the Syd Barrett of his time.
Overthinking in my case was never much of a gift, especially when paranoia enters the mix. It turns every little thing in life into a complicated issue and can be very draining. Fortunately, the only thing that really helped counter-act this for me was meditation, give it a run. Best of luck