been TTC for over a year, hoping this would be our month but I’m confused if it’s IB or AF? .. please help 😬

I had light pink spotting on 02/01 with slight cramping, yesterday it got to a dark brown color and today it went from pink to slightly red.. AF is due tomorrow, 02/04, and I’m a HEAVY bleeder so I’m not sure if this is IB or AF starting to show up early.. btw the spotting/bleeding isn’t enough to fill up a pad so I was wondering if it is IB, can it last more than 2 days? cause this would be my 3rd day spotting/bleeding on and off. 😐