I have always had irregular periods. Usually they are very long and pretty far apart. I didn't start tracking them until recently, however. My last period started October 18 and didn't end until November 11, so 3 1/2 weeks long. Now, just a week later, I have cramps and bleeding again. What is going on? Why are my periods still so irregular (I've been having periods since I was 9 or 10, and now I'm 15)? Please help.