I'm usually incredibly regular, every 27 days on the dot AF turns up. We're on cycle #2 ttc #2 and I took about six months to fall with DS so not expecting anything. First cycle my period was 4 days late when it did start it took ages to get going, very light period for a few days then some heavy bleeding. This month my period was due to next Wednesday but on Friday I started some very light bleeding when I wipe which is continuing.
My question is firstly, why would I suddenly have a late period and now an early one and secondly, when trying to calculate my days for next month do I count from Friday or whenever I properly start bleeding?