Do your OPKS get lighter right before your fertile window ?? I don't think I've ovulated yet, AF ended On CD7 , I'm now on CD21 & Glow says I should be ovulating tomorrow  ? My second line on my OPKS have been getting darker , just not the same color as control line , and then all of a sudden , are very light. I've been testing sense AF ended , so I don't think I've missed my ovulation peak. Just very confused , why my second line on the OPK are getting lighter now ?? Any advice? Thanks !!