You probably ovulated late. If you've been under any abnormal stress lately, that can have an impact.

Sometimes it takes time for the levels of hCG to reach a point that a pregnancy test can detect them. I think I tested when I was 2 days overdue and it was negative. By the third day, it was positive but very faint. I took the other test on the fourth day and it was definitely positive.

I would buy a couple of different brands and test today.

Did you ovulate late?

The test should have been positive unless you ovulated very late or the test was a dud. I would try again with a different brand in a day or two.

So, I'm 7 days late but I took a test when I was 3 days late and it was negative. Could that test have been wrong or could it not have shown up yet? Just wondering what the heck is going on.