Do you ovulate after a miscarriage or get your period first ?


Can anyone help me, i miscarried at 5 just before Christmas, it was my first pregnancy and I have very irregular periods. The doctor explained I would have to wait until my next period to try again as I won’t ovulate again now until my next cycle. It’s been 6 weeks since I started bleeding and I have had no period but got a positive opk today, will I ovulate ? Every where I read says that you ovulate before your first period after a Mc, so why did my doctor tell me otherwise ?