Hi bigfatbump, really sorry to hear your story. I was diagnosed with MMC at 13+0, on 21st Sept, where I was told the pregnancy had failed at 8+0.
Expect to be in total shock for a good few days; it's a huge headf/k to realise that all your expectations for breaking the happy news, and your plans for the next 6 months which you were finally allowing yourself to believe, have been wiped out, but to find out from a scan rather than your body miscarrying naturally feels like a seriously cruel betrayal.
foundintranslation's advice is sound, and I would highly recommend an ERPC if possible; I was given one on Monday, (2nd Oct) and can't believe how quick and easy it was. I haven't even needed painkillers since, and psychologically it's been great as I feel that I can get back to square one. Although I wasn't worried by the idea of having the foetus inside me, I did feel that while I was carrying it I was in a state of limbo.
I brought on bleeding myself, prior to the op, using raspberry leaf tablets and tea. If you've already been given medication, then I would hesitate to recommend this, but for anyone else who reads this and is awaiting an ERPC, I would totally recommend it. I felt like I had some control over my body, and that the ERPC would be less of a shock to my system if the cramps and bleeding were already happening. I didn't pass any tissue in this time (1 week), but was mentally prepared that it might possibly happen.
My heart goes out to you, bigfatbump, and hope that you recover both physically and mentally in super-quick time...