Just got back from my scan, and all is well in the end . We saw and heard the heartbeat.
The sonographer was a really fishfaced middle aged man. He put the probe on my tummy, then said "Oh it's too small, I have to do it vaginally." Said in a serious voice. Cue me nervously asking if this was normal at 12 weeks. He sent me off to pee and undress. Then when the vaginal probe was in he said NOTHING for about 2 minutes. I was craning my head around to try and see the screen, but it was a bit out of my range. Then suddenly I heard a boom boom boom kind of noise. I had to ask him if that was the heartbeat. Oh yes, he said. So, phew, it's alive. He then reeled off a load of figures to the nurse, with no attempt to explain them to me. When I asked him, he said that it would be passed on to the obgyn and they would call me if necessary.
The bean is only 4cm, which I think is quite small . I asked him if it was all ok, and in his best "I'm not going to commit to anything" tone he said that all the measurements were in the normal range for this timescale.
I was REALLY worried it was a mmc because I've been feeling completely normal for the last couple of weeks. No nausea, normal sleepiness etc. So, ladies, if you're like me there is hope. Some of us are just "brutas" as the Spanish say (sort of insensitive/crude/not affected by much).