So confused...

Hey ladies... AF was supposed to come on Monday (28th) but showed up early on Christmas eve and I only bled for one day. It was so weird! AF is always on time and last for 5 days.  I don't think it was implantation bleeding since it was bright red and medium flow. And I took a hpt today and it was a BFN. Anyone else experience this too?? I'm also experiencing a lot of bloating, nausea and I'm always tired and hungry.