Need Advice please ladies

So, 10/20 I had miscarried. I was bleeding for 8 days and hcg numbers were declining. They also did an ultrasound and was told everything passed and I seen nothing in uterus. However, I had sex 10/19 day before bleeding for miscarriage. Went to doc yesterday for another hcg level and got a call last night that it went back up to 496. So, they wanted ultrasound today. Went in and there was a 3 week sac this time. I ask doc for progestrone to help me from not to miscarry. He refused, stating he has no clue was going on. I felt hurt and like he isnt doing all he can to help me keep baby in. What do yall think? The 496 was yesterday. Could this be a me pregnancy from 19th as odd as it sounds. He said no way to ovulate right after miscarriage.