Delayed ovulation?

Hi ladies!

In May I got my period I was due for my person on June 20th however I’m now 10 days late. I’ve taken 3 pregnancy test all at different times within these 10 days, the last one being yesterday (6/29) all have been negative. I’m not sure what to do or think as I have a vacation coming up this weekend. I have been under stress and this pass week have been taking it easy. I’m not sure that to do. I’m the type of person who needs her period to prove no being pregnant even though 3 tests have told me I’m not.