Delusional to have hope?

Maria

So we have another ultrasound tomorrow (app says 7 weeks, 5 days). Our HCG Numbers very low, 312, 527, 716 and a yolk sac at first u/s, then fetal pole and small sac at second u/s. Tomorrow is to see if there is a heartbeat. If no heartbeat, then doc says it’s diagnostic that it will be a miscarriage. Has anyone had any success stories with similar low numbers and a small sac?