Brown Blood and Very Light

Okay so I'm a little confused in the first place because one app told me my period was supposed to start on Monday which would make me 4 days late. Well it's Friday. And this app tells me that it should have started yesterday and I'm just one day late. I am just today experiencing some very light brown bleeding mixed with CM. This is not typical for me. We have been TTC this month but am I getting my period or what is this weird very light and brown bleeding?