I have been on birth control for 4 years and my period has never been irregular. It starts a few days into the "sugar" pills at the end of the pack, and lasts for about 4 or 5 days. But this month it started after just the first week of pills from the new pack, and has been going on for 11 days. I don't know what's going on. Could I be pregnant? Is it normal to have an irregular period out of no where?