False Positive?

Ma

Last night, I took a First Response digital pregnancy test. It sat there and did nothing for about 7 minutes, so I picked it up and a yes with a clock was displayed. I took the same brand of test today and it says no. I really need help understanding if these are faulty tests and if anyone actually was pregnant when the same image came up for them! Ive read online that this brand of test is terrible and does this frequently!