ttc after miscarriage

I had a MMC earlier this month. I opted for medical management so I've just about stopped spotting 3 weeks later. I'm just wonder when I can expect AF? Hospital said 4-6weeks - is this from MMC or when I stopped bleeding? It took us a year to conceive so we want to start trying straight away and I'm being impatient! Thanks in advance for the advice! 
Edit: MC was at 12 weeks, measuring 10 :(