Very prolonged Period

I'm very worried. I'm 28 and I gave birth to my Daughter on Dec,16th of 04. My periods regulated when she was about 3 to 5 months. But since the beginning of 06 my cycle has gone berserk. See, I thought I was preg. in the beginning of 06 but turned out I wasn't. I thought this because I had missed my period by about a month and a half. Since then it's gone berserk. It started something like this: Period comes for 5 days then goes for 2 days, period comes back for 2 days goes for 2 days. Since then about the past few months especially now it has not stopped. It has been very light til recently. And for the past few days it has been getting heavier. I don't believe I'm preg.(obviously can't be)  I have a gyn appt. coming this month. I don't want to take meds because I have low tolerance to stimulants. Does this sound familiar to anyone? Could someone please tell what this very prolonged period may be related to?