False positives

Has anyone had experience with false positive pregnancy tests?  I am 5 days away from my period and took a pregnancy test and it seemed the test was moving really slow so I set it down and left it. It was past the test time for reading but it was showing positive. Is this normal that antsy would read positive if it's really negative? I don't want to test again for fear if being disappointed yet again this month.... :(.   Am I fooling myself?