6 days late now what? (Must read)

Ok I'm 6 days late now. I've been having cramping and back aches. It feel like AF is coming but haven't. I had tested when I was 3 days late but I got a BFN. Should I text again? The nurse at the doctor told me to wait till 2/4. But I just can't help myself. Have anyone got a BFN and tested again  days later and got a BFP?