Weird Bleeding

Okay so I'm not due to get my period until next week. About five days ago I spotted in the middle of the night. Just a tiny bit and that was it. Then yesterday I started to bleed. Today I'm in so much pain. My back and stomach hurt to the point I could cry. When I use the bathroom or I'm just bleeding stingy blood comes out. Its not like normal blood it looks like a sting. Is that a blood clot??? Could I be pregnant or something?? Help!

Other info - I'm on the pill birth control. I've been on it for a year and my last set of the pack is the "period" pill. So my periods are ALWAYS the same and on schedule.