I used to be a victim of this myself. My solution to this problem (which works very well) is to lead a life of strict routine, where every hour is allotted for doing something specific. As I stuck to the routine, this whole overthinking thing magically disappeared as I simply didn't have the time to overthink. Everything is also progressing 10 times faster as well. I can't guarantee that it will work for you too but it's worth a try.