Hi Folks! Congrats on all the lovely scans! :0) And good luck tomorrow Bonjour and Banana - and anyone else i've missed with a Thursday/Friday scan!
( am with you on the FB thread thing btw Bonjour - enjoying the anon.. anonymity (..? Spelling fail!) of MN for now.
Cinnamon luna is right - you shouldn't be fielding crap from your sis-in-law when it was DPs job to sort it anyway. You've enough on your plate!
Janey, just wanted to say, don't feel alone in feeling rubbish, and don't hesitate to share those feelings on here, and with whoever will listen.
It was a relief to me to hear from someone in the same boat really - I just haven't been feeling myself for weeks now and felt really down in the dumps the last week or so, to the point that I even postponed breaking the happy news to DPs and mine's Mums/Stepdads - the bit I'd been really looking forward to. So I'm now 14+1 and they still don't know (tho hopefully I will get my act together this weekend)!
I don't think these feelings are helped by hormones, work-stress and just feeling physically exhausted, which naturally makes you worry about how you'll cope with a baby (if you don't already have one!). I don't know if anyone else here feels that they are just.. missing their old self, and wondering if that person will ever return....?
So, yeah, Janey, just keep talking to people. I felt like I shouldn't feel down when I have lots to be grateful for and there are so many folk desperate for kids out there and still trying, etc.
But in the end I put this guilt to one side and chatted to DP at length who has had his own battles with the blues in the past and was fantastic. I find gentle exercise helps a bit too. Feel a lot better the last couple of days. So just... find a friendly ear wherever you can, and don't feel bad for feeling blue. Like I say, it was certainly a relief to me to hear someone else on here say they felt less than great. 
londonlivvy Must admit, had a mixture of jaw-drop and giggles at your Mum's response! So far, we've had 'was it planned?', and DPs dad being more concerned that he's old enough to be a grandad than about the actual baby - but that one takes some beating! :0D (She has warmed up since, I hope? :) )