Slow rising hcg

Hi all, this is my second pregnancy the first unfortunately ended in miscarriage. I went in for my scan at assumably 8 weeks but ended up showing a twin pregnancy measuring 6 weeks with no heartbeats. My OB told me she has minimal hope this will be successful pregnant but I have another scan next week to confirm. My hcg was 63,000 the day of the ultrasound with progesterone at 17 and 65,000 hcg 48 hrs later. My OB has no hope and I’m curious if anyone has a similar story with success? Or should I prepare to miscarriage as the OB said