another OPK question...

Okay so it's my second time buying clear blue digital so I now have two sticks to test on  yesterday's reading has a solid smiley (for peak) and today I used a different reader since the solid smiley stays for 48 hours and this morning when I tested it already has a blank circle for not fertile 😔 feeling sad, is there any use trying again tonight? He only time we BD was last night (8hrs ago) I feel like I missed the window ):