Late period!

I've recently come off of a progesterone only pill, it's been 35 days (5 weeks) since I've come off of the pill, and I haven't had a period yet. I had some spotting when I wiped myself after having a wee, however there was no other sign of bleeding and hasn't been since. Has anyone else experienced this? Also I've taken pregnancy tests for the past 2 weeks and have had negatives each time!