Not the news we wanted

Came to ER for some pubic area pain and 4 days of brown discharge.. u/s measures baby 5 weeks which according to my charting I should be 8w3d... yolk sac and fetal pole all was there but no visible heartbeat yet.. we are unsure if baby is still growing or has stopped. Need to recheck beta in a week. Has anyone miscalculated and gone on to have a healthy growing baby? Looking for some hope... thank you!!