Positive pregnancy test then negative pregnancy test

Sara
We are TTC and would love some feedback: This morning I peed without taking a pregnancy test (half asleep), took one the second time I peed and got the light double line (signifying pregnant, I believe), then took another test the third time I peed and got only one line (not pregnant). 
Below are the pictures. The top test is the first test I took, the bottom test is the second one I took about an hour after the first.
Has anyone experienced something similar? My period isn't supposed to start for a few more days.
Thanks for any feedback!