I think you may be having a wacky cycle due to not feeling well. I see that you have illness and fever marked on your chart a couple of times and that may have been a contributing factor. I am curious about a couple of things though...have you done a pregnancy test recently? Is your son still nursing like he has been or has he (or you) been weaning from BF'ing? Because pregnancy (even if it was a chemical) and your son changing nursing patterns can affect your cycle.
If nothings changed and you are still not feeling well on Monday, I would definitely call your doc and see what they say. Keep us updated as to how you are. I hope that your body straightens itself out soon.