I have noticed that my periods have changed and become a bit more irregular since begining this wol, especially since I have increased my exercize routines. I would not worry too much unless there may be other cause for worry (ie. pregnancy). I am not on any form of bc either (don't like the hormones), and my periods have become lighter, and a bit more irregular. As your insulin (the master hormone) regulates, it will result in other hormonal regulation that can take some time, and result in some shifting of what we were accustomed to .
If you continue to be concerned, perhaps consult a healthcare professional. Good Luck!