Missed miscarriage how long will take body to start expelling after a missed misscarriage

Hi All,
Yesterday in my scan we found out that I'm having a missed miscarriage.I was about 11 weeks but the baby had stopped growing @ 7-2 weeks and there was no heartbeat.Since my cervix and internal os is still closed my doctor had asked me to wait till that gets opened and bleeding to start.But this wait is killing me.I was also on progesterone supplements and now doctor had asked me to stop those. Can anybody help by telling approximately how long will it take the bleeding to start after stopping the suppliments?

Thanks
laks