Thin line

I've been using pregmate for little over a month and a half now. I know they can give an indent line but this morning I got a test that could possibly be the beginning of a positive but its very hard to see and had no color that I can tell.

Within time frame. I took another and it had color, but its pencil thin.(Not sure if I can get a clear picture of it.)

Has anyone that's used pregmate experienced this? What was your outcome. Just curious and yes I will test again tomorrow but just wondering if the test is invalid.