Positive OPK 11 days after misscarage what does this mean?

I have just now recovering from a blighted and Iam 11 days out of a miscarrage! Could I be ovulating this soon? I don't go into test my hCG level again in till the 31st I tested about a week ago and it was in the 500s. I did get pregnant with my 18 1/2 month old now about two weeks after I miscarried before. Can you still ovulate without your hCG levels being add zero or are they at zero and I just don't know yet because I don't tested again until the 31st. Dr. doesn't want me to start trying again until she sees my hCG levels at zero. Idk what to do this is such an emotional  and confusing time for me. Would love to hear some advice please