messed up period.

I took plan b like a month ago and everything was fine with that. I was worried naturally but I soon eased back. And I started getting brown discharge at my regular period time and I was like okay this is normal and the next day it turned into slightly heavier (not much) reddish bleeding. Which is weird cuz my periods are crime scenes. So later that day it was heavy bleeding (normal) put a pad in and slept. Woke up and there were some saturated patches on that. And then comes today where my tampon wasn't soaked when I pulled it out and now it's back to super light bleeding. Is this cuz of the pill? I know it affects your cycle but it's odd for me