What is going on?! 😩

So Glow predicted my AF to start the 24th, Ovia predicted 27th, have been suffering with mild cramping and slight nausea from about a week before the 24th, tested on 25th it was negative, yesterday (28th) cramping was slightly worse but still no AF, tested again today and still a BFN. My AF is normally spot on! Could I still get my BFP or could it be because I am not in my usual routine i.e being off work due to the Xmas period and being slightly lazier? What do you think ladies?