TMI! What is this?

Hello, I had a MMC back in May of this year and DH and I have been TTC again since then. I have had some crazy weird cycles lately. I'm on CD 24 now, have been having average of 18-19 day cycles. I had light pink spotting on Saturday CD 21, and have had light brown spotting since then, pretty much only when I wipe and doesn't even fill up half a panty liner a day. What could this be? I'm not calling it a cycle because I have had absolutely no bleeding or period symptoms!