AF late and going crazy?

AF was due monday and has yet showed up. I took a HPT Tuesday and it was BFN and then an hour or two later is was BFP. Then I bought a digitual one and it said not pregnant. I've been working out and lost alot of weight. I'm in the process of joining the navy. I'm just going crazy I feel like she goingto start any min. My cervix is low and I've alot cm.