How long until miscarriage happens?

To anyone who has had a miscarriage:
How long until it gets started? I have been spotting on and off all week and today the blood turned pink and red. My doctor said there isn't any blood in my canal and my cervix is closed, but she said it could go either way. I am only 4w6d so she said if I do miscarry it will feel like a heavy period. I have been experience period like cramps for a few days and today they're a little worse. Pink, watery discharge is there when I wipe. How long until it really gets going? I just want to get it over with so I can move on. Any one have a similar experience?