How long does it take for hcg to go down after miscarriage

How long does it take for hcg level to go down after miscarriage it’s been 3weeks since I passed the baby October 27th and went to the dr and the gestational sac and yolk sac a lot of it was gone. I did have sex November 6th and October 27th . I would told by my dr to take a test two weeks after and it’s actually 3weeks and I’m still getting a positive test . Should I wait another week to take another test or is it just that my hcg level didn’t get to zero yet .