Bbt continually drops after ovulation

Monica

I had positive Fern tests, positive opk strips and my clear blue fertility monitor also showed peak this past Friday/Saturday....I felt the pinging on my left side, diarrhea all Saturday etc. I'm still feeling slight pinging on my left side but my bbt is continually dropping. Is this normal? S/n: I just took a opk strip and used the clear blue monitor this morning and both are now negative... What am I missing here?