Huge dip 5dpo

Melissa • Mother of 1 two year old 🌈 and 4 👼🏻 🌈 #2 due 12/23/19
My temps were slowly rising until this hugh dip today at 5 dpo... Almos have a ton of ewcm yesterday and today.  Pretty sure I o'd 5 days ago as opks have been quite negative... Any thoughts on what might be going on here? 5 dpo is too early for an implantation dip right?