Irregular Period.. which has never really happend to me before

I am 22. 1 child. My husband and I are sexually active. I had my period on the 26th. But, it did not start out as it always has, which would be pretty heavy for the first two days, moderate for a day and a half, then down to almost nothing on the last day and a half. Instead, it started with light brown spotting, then a little red blood spotting. On the first day, then all day nothing up until the evening on the 27th then I got a heavy bleed which i thought I'd be back to normal. But, it didn't last but over night into about 1 or two that afternoon. Then it went to moderate bleeding for half a day, then almost nothing on the 28th and 29th. On the night of the 29th it got moderate again for about 2 hrs.. Then stopped. The next day, 30th some brown spotting. The 31st nothing.. I thought it was over. Then yesterday, 1-1-13, i started spotting brown again in the evening. And i was still spotting and it had been accompanied with moderately uncomfortable cramping this morning 1-2-13... Any ideas??? My periods are never irregular and they last 5 days... thank you..