what is going on with me

I'm so confused. I should of started af by now still haven't, I was assuming I'm going to be about a week late. But idk. I've been reading you have a high tempature when your pregnant and it drops before af. I've had a high tempature for the past two days now. My boobs are starting to feel tender but nothing major, I was having some cramps, heartburn, I've been getting headaches/migraines for the past week. And today I've been feeling randomly nauseous, but just a bit ago and now I feel like I'm going to puke. I've taken test and they've all been a bfn. I'm not getting sick, I know when I'm starting to get sick and I haven't felt anything like I do when I get sick. And I haven't ate anything bad so there's no reason for it. I'm so confused why I'm feeling like this with no af and Bfns. I'm not stressing to delay anything I've just been more like okay wth why didn't I start af today, but oh well maybe tomorrow.