Charting after going off the pill/long term pill use

Megan
I'm charting for my first full cycle after going off the pill. I've been on the pill for 13 years and had very painful cramps before I went on it.  I stopped the pill in Nov and had a period/withdrawal bleeding Nov 17-19 (short and not super heavy but I wasn't having heavy periods before the pill or on the pill).  I didn't chart Nov- Dec.  I had another period Dec 14-16 (so a 27 day cycle) assuming that what I had in Dec was a true period-- again, 3 full days.  My cramps werent bad either period but I had TERRIBLE debilitating headaches. I started charting on Dec 14. 
I'm now 21 days into this cycle and no temp jump-- I'm wondering if I should be expecting annovulatory cycles for a while with 'periods' or long cycles back against short cycles or what -- what have others' experiences been with charting atet going off the pill following long term use? Thanks much!