Kind of freaking out

KMLP

I had a bad m/c dream last night, so for some strange reason, I thought taking a test this morning would be reassuring.  So, I took one and the line is super light.  I haven't had a line this light since 14 DPO or something.  WTH?  I've been googling and I've found a lot of things that say once you reach a certain week, you can get a light test, but I'm still freaked out.

Also, I've used these tests during this pregnancy, and the last test I took at 19 DPO was super dark, so I don't think there's anything wrong with the tests or anything.