I was 15 weeks! I went for what I believed was my 12 week scan, and was told that I was actually 15 weeks pregnant with two!
I hadn't had any morning sickness, and had not put on any weight at all at this point so it was a big shock!
I had seen the midwife a few weeks prior to the scan, and had the heartbeat check, and only one heartbeat was detected, so I had no reason to think otherwise.