Help?!

Since starting Alesse 28 combination pills at the end of February I’ve had one period about halfway through my first placebo week. The whole thing has been nothing but smooth sailing thus far. Then on Sunday night I noticed some light bleeding and figured it was just my body adjusting to hormones as tends to happen in the first few months. By today, though, since it’s gone on so long and it’s been soaking tampons all the way through as if it’s a regular period, i’m really stressed. Could it be my period, if the pills aren’t working or something? How worried should I be??