esme You always show sooner with 2nd & subsequent babies. The urterus starts to rise up behind the pubic bone between 10-12 weeks, so yes - by 13 weeks I'd expect to be showing.
I managed to get through Christmas day OK by just nibbling on little savory things through the day, and didn't overdo it with dinner. Still felt rather queasy come bedtime though.
We broke the news to DD3 that she's going to be a big sister at the start of the summer holidays net year, and she was really excited. She got a bike for Christmas too, so she kept telling us this was the best Christmas ever!
OH couldn't get through to his parents in Australia on the phone though, so he had to break the news to them by email. He got replies back yesterday, so he went on Twitter & Facebook to tell anyone who'd listen that he's going to be a dad again. He's been bursting to tell everyone since we got the BFP six weeks ago, but I wouldn't let him as I had my first MC at 10 weeks on Christmas Eve 14 years ago (and boy am I glad we seem to have laid that little ghost to rest, though I know there's still a risk yet).
It's nice to be open about it at last now. 
10+1