First ultrasound tomorrow

Please pray for me. Tomorrow we find out if this pregnancy is viable or if I’m going to have another miscarriage. My hcg beta numbers haven’t been doubling: 12/14: 83, 12/20: 548, 12/22: 747. My doctor said that things could be perfectly fine or it could indicate another miscarriage. Hopefully we’ll be able to see our little nugget, I should be 5w4d. ?????