K, I know EXACTLY what you mean! I've been working on a mariners compass quilt. Have four of the six compass' complete. No problem, went together like PB&J. The fifth one is KILLING me. I cannot sew on the right line! I can't position my fabric correctly. I have ripped more than I've sewn. So, I put it down for now and have moved on to something else. It's still sitting on my table, to entice me, so it won't become a UFO, but I'm not picking it up till I'm good and ready again!
Put it down for now and do something else small, then come back. And good luck!