HCG levels

I started having a miscarriage on June 1st and by June 16th it was completed. I had my final ultrasound and everything was completely out of my system. They did not check my hcg levels and I know everyone is different but I’m wondering how long it took for everyone’s hcg level to come down? I’m also waiting for my period to come back, they said it could take 4-6 weeks to come back and if I still haven’t gotten mine in 8 weeks, to give my md a call.