Really Weird Menstrual Cycles?

ever since December my periods have been really weird.
I got my period on Dec.1 and it ended Dec.4th it lasted only 3 days from my regular 7-day period.
Then I got my period (Again) on December 25th
That period lasted for 3 weeks. It was heavy with clots and it caused a lot of cramping.
It ended all of a sudden 2 weeks ago on December 18th.
Now I got my period again!
What is wrong with me?! Has anyone experienced this?
I'm not on any birth control that may have caused this.
I'm 18
Any answers will help. Thanks.

Anonymous2011-02-03T17:54:17Z

our body works so different all the time, it sounds like your hormones, but the only way to be sure is to go to your doctor. It can be many things, good luck hun