Period on bc (not on sugar pills yet)

Morgan

So I recently started birth control, about 3 weeks ago. I started the 3rd week row this past Thursday and yesterday I had light bleeding almost like a really light period. I get that that's supposed to happen, but not till the 4th week which is the sugar pills right? I really dont know

I take Tri-Lo-Marzia from Lupin if that helps or if anyone has experienced similar things.

Edit: also I never missed a day, skipped, or was late on taking the pill