5 days late on my period and 1 negative pt! What’s going on?

Rea lykka dgreat

AF was supposed to make an appearance 5 days ago but it didn’t , so I’ve decided to take the test this morning around 4am and it was negative. Plus, I usually get pms before my period is due but I haven’t getting any at all, well except for extreme fatigue and light headedness on and off.