.......Stupid evap line........?

I've been taking the same brand test every two days, all negative. Don't ask my why (according to peeonastick.com I'm a serial POAS-er LOL) but I kept them all. All of them still look the same. But one, just one, the one I took yesterday has an evap line. And a dark one at that! It makes the test look like a definate huge BFP, not faint.. So of course for a split second my heart skipped a beat. I KNOW it's an evap, isn't it? A lesson to all: throw the test away after 10 minutes!!!!