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.
2. To become seemingly trapped or stuck in a mundane, non-changing pattern of life, work, and/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!