Has this happened to anyone else???

I have been using the dollar store tests, mainly because after 9 months of TTC it's cheaper! :) and I've heard only positive things about them from friends, co-workers, and even posts on here...

Four days ago I used one and it had the control line, and then a very faint single thin line beside it... I double checked the next morning with a first response test and it was negative. I waited a day and took another dollar store tests and it had a 1/2 line on the test side... figured it was a faulty test... so I took one last night and this is what it looked like. I realize this is a 12hr old test; however, it looked exactly the same last night... I just didn't take a picture of it until this morning.

Speaking of this morning... it appears I got my period.. so I think the three dollar store tests I've used that gave me these mysterious thin lines are just coincidently faulty...

Thoughts??