Positive to Negative?

Cristal

Hello I was wondering if this has happened to anyone and what the heck is going on. So I take one pregnancy test and it's it completely positive. The next day I take the other test and that one comes out the same way very positive but then I look back an hour later and the line had faded almost completely gone and now it's pretty much nonexistent? Would anyone know if it's positive or negative? The first one stayed positive.