4 bfn

I'm only due for my period on May 7th but I've taken 4 hpt, one at 6dpo, 7dpo and now 9dpo and 10dpo and there all coming back negative. I've been pregnant before (without trying) so I'm not exactly sure when I ovulated or how late I was with my period when I tested, but my body is feeling very unusual. Along with the boob tenderness, fatigue and nausea. My stomach has been bloated and I've been unnormally queasy, not just the simple nausea but the everything I eat or sometimes drink like diet iced tea all i can think about is getting sick.