My pregnancy test was a faint negative and turned to a very bright positive after the time limit elapsed?

I have taken the same type of test 2 days in a row. Yesterday, it was a faint negative. .I had to peek after the time limit. .It was still negative. Today, I took one as soon as I woke up. It was a faint negative but became a very prominent positive after the time limit had elapsed. The test is a +/- with blue dye. Both lines are clearly blue. Help! Please and thank you!