I started Chateal (birth control) roughly 3 months ago. Last month I had a period lasting about 2 days which is abnormal. But about a week ago I had unprotected sex and started spotting the day after, I continued to spot for a few days and started my period. But I'm only on the first week of this months pills, making my period 3 weeks early. Could I be pregnant? Should I be worried?

It could be that you're pregnant. Having a period while on birth control is a little odd. Does it conform to your regular periods?

Honestly, I would abstain until you figure this out and figure it out with your doctor. The advice usually given is to wait until after a missed period, but it is sounding like you're having a period which is the best Not Pregnant sign out there.