OPK help...

Marianna
Soooo I started testing with opk on cd10. I am now on CD12. It's been increasing in darkness til yesterday... But today it's lighter than it was yesterday  Is that normal? What could that mean? I don't think the one I took yesterday was positive because the line wasn't as dark as the control line. Is it possible I already ovulated last night? I got some sticky egg white cm today too...