BBT expert needed :) quick question

Brittny • 1 1/2 yr old
Is it typical for after your period to have a big drop in your bbt? I'm 2 days past AF and temp dropped 1 full degree over past 2 days. Doing opk testing but haven't yet today so it could be possibly I'm ovulating really early this cycle.... Maybe... 
​Thanks for any input! trying to fully understand bbt through the cycle:)