Why am i getting so many evap lines?

So i have taken probably 500 plus test on my time and i have never seen and evap line before. I would stare at test for hours even tho i know they were no good after 5 mins and still never saw one. Now i have taken 10 test over 2 and half weeks and i have gotten 7 evap lines on 4 different types of test 2 blue and 2 pink dye test. So now has anyone had this happen and actually end up pregnant. Im 2 and half weeks late have had spotting after sex cramping back pain nauseous and way more tired then normal. Please help so confused.