Hcg levels

So question for you ladies, I had a miscarriage in October and I now am having positive pregnancy tests. So they had me do blood work today to see if my levels went up and my hcg level is at 506 (for 4 weeks and 2 days), and my ob has no idea if it’s a new pregnancy or my old.. said they were gonna have me redo my blood test in 2 days. What do you guys think? New or old pregnancy? & would it be normal for my hcg level to be at 506 a month and 2 days after my miscarriage? Please any info would be appreciated 😊