chase your tail

chase (one's) tail

To take action that is ineffectual and does not lead to progress. Refers to how a dog can exhaust itself by chasing its own tail. Come on, Bill, go to sleep. You're just chasing your tail at this point, but you might have a breakthrough with the research if you take a break from it. I'm trying not to chase my tail on this project, but so many components of it are just not working out.

chase your (own) tail

keep on doing something futile. informal

chase your (own) ˈtail

be very busy but in fact achieve very little: In my first month at college I was continually chasing my own tail and being late for everything. ▶ ˈtail-chasing noun

If a dog or cat chases its tail, it runs round in circles trying to bite its own tail.