I think; therefore I have a headache. Suffer from over-thinking? Guilty of the thinking much? Or, just ... meh.
I think a lot. I am an introvert so I work things out more in my mind than out loud. But I would not say I am an over-thinker. In fact, I am pretty decisive about things. I make a decision and go with it, really not thinking back on the decision much.
I don't talk with others much about what I am thinking, either, which drives a lot of people around me crazy. I have a pretty intimate and close relationship with God so I talk to Him about my "stuff", mostly in my thoughts.
I do my best thinking in the bathroom ... always have ... while I am getting ready. It's quiet there and one of the only places I can go to be truly alone. I can solve the whole world's problems while putting on my makeup. I have made many major decisions in my life while blow-drying my hair.
I also do lots of thinking in the car. I can drive hours without even turning on the radio or talking to another person. In fact, I prefer the silence so I can think.