Miscarriage

I would of been 12 weeks pregnant now I found out two weeks ago my baby stopped growing. I am booked in for a d&c; next week but today I started bleeding bright red with cloths it has lightened abit now I just want it over with does it start and stop usually? Doctors put it down to a missed miscarriage, also when can you start trying again after a miscarriage we really want a baby tia x