When to test again?

Okay. So. I ovulated 19-25th of November, and in this time period I had unprotected sex. AF was due 4 days ago, and has yet to show up. I’ve taken multiple preg tests, all came back negative. So I wouldn’t be stressed if that was it. Except for I had unprotected sex last week on December 5th. When do I need to worry about testing again? I should note that I do have irregular periods, so AF not being here yet isn’t too odd for me, but it definitely makes the whole pregnancy scare a little more difficult. I guess ultimately the question is, how soon after sex does a pregnancy test work?