Confused?

So I think my period just stared or it may just be spotting? it’s a week early. There’s a lil blood in my underwear and a lil blood when I wipe. But I’m never early I’m usually late in fact. I am on birth control I just started about 2 months ago, could this be making my period start earlier? I thought that with birth control you were only supposed to get ur period when ur on the week where you don’t take the pills? I haven’t missed taking them, and have taken them at the same time everyday. So is this normal, or should I be concerned