BFN...

So I took a test dis pass Saturday before work and I seen one line and so me I know it usually takes three minutes to finish but I was like o well it's done... Went to finish get ready for work and bae comes in and like are u pregnant... I said no... I took three tests dis week and the one this morning is negative... He said this one is still wet and I see a line... I thought it was one of the old test but I still don't believe dat line was real.. How long after a test is taken is it no good?? It was only out bout 10mins if dat...