Brown spotting! Help!!

Rachel
Thus is only my second month ttc off bc so I can't say for sure that I am late. Last cycle, the 1st one, was exactly 28 days. Which I know can happen after bc. So cd 28 would have been the 4th. I have been having brown spotting only when I wipe for 5 days now, so started the 2nd. I took a pg test yesterday morning and it was bfn so I plan on taking one tomorrow morning if af still doesn't show. Does anyone have any ideas what could be going on? Last cycle I spotted brown 2 days before I started. I've been having symptoms. Yesterday's temp dropped but today it went back up a little. So I don't know if that could have been implantation or what is going on. Any thoughts would be great! Hoping this could be our month!!