What can cause a late period that is not pregnancy?

What can cause a period to be late when you are not pregnant? I have missed my period for 10 days and it is always on time…all tests are coming back negative

Stress, anxiety, hormone imbalance and for me, if I’ve been sick a lot it can run both late and early. It just depends. It’s weird, I know.

Hormone I’m balance, stress ,.enopause if your old enough

Stress. Hormones. Medicine.