The mind can be tricky. It can be a relief to understand that thinking is what causes upset, not circumstances. However, if you try to stop thinking, you’re only getting deeper into thought. It’s tricky.
I believe it’s best to not let it bother you. The easier you are on yourself about your thoughts, the easier it is to not let them run you down.
Try not to overthink it. And definitely don’t think too hard about not overthinking.