Just when you think you know, you have no idea

Krystal • Wife and mother of a 6 year old girl
Thought I was sure I was getting the hang of knowing my cycles since I've been taking opks and bbt. Got my positive opk saturday, temps have been gradually going up since . Today it spiked and I'm like o yea! Then I go to the bathroom at work to notice I was spotting. Started off red and then been brown light spotting and now it has stopped so its not AF. Temp is high with spotting!? I just don't know.. any help