Help! Another chemical? BBT drop

My temp dropped this am and now I’m freaking out. Had a chemical in December, took a while to get my period then got pregnant next cycle (this cycle). Still breastfeeding my 13 month old. First test is this am (12 dpo today) Second test is yesterday afternoon (which is darker than yesterday am). Anyone see a chemical coming on their bbt chart before it happened?? Thanks for your help!!