OPK +/-

Brooke • Happily married since 10.20.2012 and currently TTC baby #2! ♥️
I have a 38 day cycle and expected my +OPK around CD23 but got this on CD19. It's the darkest it has ever been and went back to being light thereafter.  I am now on CD25 and still having negative OPKs... Could that have been my surge?? Would that be too early??