Opk' getting darker but IC's still negative?

Emma ❤️💛💚💙💜 • Me and my wife are TTC baby number 2 via artificial insemination! :)
Is this a good sign?
It's not normal for me to get dark opk's until a few days before I actually ovulate! But my eBay tests are still negative! What's going on?
I'm due my period today/tomorrow!