I’m late & I need advice!

Okay, so my periods are always on time. Usually they come a little early (by one or two days than predicted). I am never late. Even with stress and whatever else, my period has always started on time.

With that being said, I am on day two of my period being late. I took a test this morning and it was negative. I guess my question is, is how long should I wait before I take another one because I know that it doesn’t always show that early. My best friend found out before her missed period whereas my cousin didn’t find out until two weeks after her missed period.