Why cant my body act right?!

I'm currently 8 days late for my period. I took a hpt at 12 DPO and again when I was 6 days late and both were BFN's. But I'm cramping worse than my normal period cramps, my boobs hurt, I'm SO tired- just like I get when I'm on my period, and I have felt like I'm starving one second, then sick to my stomach the next just like I do when I'm on my period.. What. Is. Happening! I have only been off of my birth control for almost 6 months, but this is so weird to me. & this may be TMI, but I also think I'm getting a yeast infection, which I have never had before 😫