Don't worry about what work will say - I did a similar thing, and apart from the 'get a telly' comments there isn't much they can say (they expect you to have another one sooner or later !)
I feel for your, it is very tiring having them so close together, we thought it would take at least as long as the first time (6 months) but oh no one night of passion later...!
I spent my second pregancy sad that I wasn't very excited (as I had been) and also sooooo knackered - young toddler/pregnancy is a rubbish mix!
The first year will be quite tough
mine are now 2.10 and 15 months and it is relatively easy now. They bring each other so much happiness (most of the time!) that I am glad now they are so close
I would concentrate on getting your first one sleeping through, (not that easy Iknow!)but vital and will make all so much happier.
then think about ways of making it easier when the baby comes...we asked for no presents but contributions so we could have DS1 at the childminders for a couple of hours a day for a few weeks. My DH had two weeks off at the beginning. etc
We also did some childcare swapping with friends, we looked after their little one for a few days before the baby came and they reciprecated afterwards (prearranged).
Don't feel guilty - it is only natural for you to be nervous after your previous experience, but I know of lots of people who had prems first time but not second - talk to your midwife about it, and think up a contincency plan so that you feel more in control about it.
good luck (()))