I've been having what feels like mild period cramps for over 3 weeks now and my period is exactly 2 weeks late today. What could cause this?

I have taken a pregnancy test. I took tests 10 days ago and 15 days ago. Both days they were negative. Should I take another test?

Update-Going to test, will update soon with results. Pray it's positive.

Another update-It's negative. I'm so sad. Now, I really need to figure out what's wrong.

Another update -Yesterday, when I tested, I actually took 2 tests, just to be sure.