Need advice

Tiffany • Beautiful DD Caroline
Does your HCG have to be0 before you ovulate again. 
They suspected a miscarriage last week. It was confirmed today. Basically my first appt 5/23 HCG 15 progesterone 2.52 2 days later started bleeding the next day 5/26 HCG had went up to 34. Not great but still doubled. Next text was 5/30 it had only went up to 54. Bad news (that's like a doubling time of 100 and some hours) told me to expect some bleeding and to come back in a week (today) to retest. HCG was down to 18. Still considered positive. But definitely miscarrying. 
Long story short I haven't started bleeding yet so when can I expect that to happen? Also when can I start trying to conceive again.