be in a groove

1. To be immersed in a particular task and thus working smoothly and efficiently. Now that I'm in a groove, I think I'll be able to finish this paper tonight—ahead of schedule! If I'm in a groove, I can clean for hours. Dad must be in a groove up in his art studio—I haven't seen him all afternoon.

2. To become seemingly trapped or stuck in a mundane, non-changing pattern of life, work, or personal behavior. In this usage, "stuck" can be used after the conjugated form of "be." I had so many ambitions when I first graduated from college, but now I feel like I'm in a groove. We're stuck in a groove—let's move abroad for the summer and shake things up! The touchy relations between the two countries have been stuck in a groove ever since the new president backpedaled on his predecessor's commitments to a new trade deal.

be (stuck) in a ˈgroove

(British English) be unable to change something that you have been doing the same way for a long time and that has become boring: While other businesses are attracting new customers, this one seems to be stuck in a groove, and has been losing money for the last two years.