What Causes Irregular Periods And Excessive Vaginal Discharge?

Hi, My periods are kinda irregular lately but not bad. Ussually just a few days late or a couple days early. I just had my period Dec. 16 (4 days late) which was heavier than they have been lately and was 7 days like normal. But afterwards i noticed i was contantly discharging to the point my pants were getting wet spots. The discharge is clear and watery and odorless. This never happens. Then on Dec 30th i had a few slight cramps and my discharge turned pink for a couple hours and then went back to normal. The cramps went away and i was fine when i went to bed. On the 31st my discharge changed and started getting a little thicker and turned whiter but later that night i got mild cramping and started lightly bleeding with clots for less than 24 hours. Now my discharge is back to clear, watery, odorless and excessive. I also took a pregnancy test on Jan 1st to rule out that i was pregnant before my period and it was negative. What could cause this. I also have no discomfort down there at all.