Been there, done that, then I hit myself on the side of my head and say "dumb blonde", even though I haven't been blond since I was in grade school. LOL. I once cut strips for an entire quilt, then discovered that I had cut them an inch too short. Well, I now have some strips for another fabric. It's frustrating, but sometimes you can come up with an alternative for the quilt and maybe end up with a new pattern. Don't beat yourself up, it happens.