How many tests is enough??

I'm going on my 5th day of missed period. I have taken 3 dollar store pregnancy tests and all have been negative. Have not been cramping like the usual cramping I go through..anybody out there that finally got a BFP after being Dissapointed with a few BFN's?? If so how long after your last BFN test? When should I test again? Any advice helps! ?