Negative pt is now Positive?????

Alexis • I am pregnant with my third baby, due in July!💙💗
I was about to take out my trash and noticed a pregnancy test from yesterday. Initially it was negative and now it has a very bright positive line...so I was curious I put on some gloves from work and found an even older test and from this weekend and it has a faint positive. Has this ever happened to anyone else and if so did you turn out pregnant??