Ewcm or sperm

Can sperm/ejaculate come out of you.a day later and look like ewcm? Or is it more likely ewcm? 1st day of my fertile window + flashing smiley face on clear blue advanced digital (high fertility) but lh strips are still quite low. I guess im wondered if i have time or whether i should bd today? (Using a donor so would have to get a baby sitter at late notice) (WE BD'D yesterday though)