2ww and sick

I tested at 10 dpo and today 13dpo and both negatives! Ovia said to test today and that Iwas suppose to get my period this past Monday. Glow said I should get my period on Sunday! I really hate not knowing when/if it's going to show and just hoping it magically doesn't each month. 😑 being sick doesn't help bc now I just feel nauseous and fatigued all day.