Unusual discharge?

Ol

So according to this app I was meant to get my period this week, although my cycles are quite irregular and usually the app is about a week out, so if I don’t immediately get my period it’s not really a concern to me. However this week I’ve been having pink tinged discharge which has got darker throughout the week, however has not turned into a proper period. I also experienced darker brown tinged discharge yesterday but today I seem to be back to pink? Is this a sign my period is just on its way, or is there something wrong? I would have been more concerned if it was just a day or 2 and then stopped, but I’ve been getting this since Sunday consistently. Thanks!!