I was on my period and a week later I was still on it but it was light but still there. It stopped for about 4-5 days and started right back up. So it's been about 3 weeks now for a total. I'm on birth control and am sexual active. I haven't had any signs of pregnancy. What could be wrong?

It could be due to the birth control... even if it hasn't happened before. You might want to see your gynecologist so that all possible reasons can be checked, such as hormonal changes or simple polyps.

I agree, too many possible reasons. And yes, could be a birth control issue but then also several medical issues. Time to see the gynecologist for a check up