Bleeding for that long would most likely not be caused by pregnancy - but some other issue such as hormone imbalance. I would see your doctor.
If it's bright red blood, you're not likely pregnant. That sounds like a sort of hormonal imbalance, from what I've read.
If it's white/clear/yellow/brownish discharge, then yah maybe you're pregnant. If your last period before this one started more than 45 days ago, I'd get a test to see. Good luck~