Late on period, negative test

R

So... I’m 40 days late for my period.

There is a very slight chance I could be pregnant from the more recent time I’ve ovulated, I planned on taking the test Sunday morning to see.

What are the other reasons I could be SO LATE but not pregnant?? Could I still be and just have been getting negatives? I took one 5-7 days ago and it was negative, but if it was from the more recently time I’ve ovulated it would only of been about 4-7 days after I ovulated.

I just don’t know why I’m so late. I’ve never ever been more than 5 days late for my period, I’m not super stressed or anything, and I’ve been working on fixing my sleep schedule.

Any ideas why?