Empty sac

Went in for an early ultrasound due to spotting. Based on when I’m pretty confident I ovulated I should be between 5w2d and 5w4d. All that could be seen was a 4mm empty sac. Dr thinks it may just be too early. Going back next week for a follow up ultrasound. In the mean time just looking to see if anyone can share their similar experiences and what the outcome was. Thanks!!