rosmerta I really sympathise - when we went on what was supposed to be a relaxing holiday my DS's sleep patterns went haywire and I was up all round the clock, and then waking at 5am French time (4am English time) for the day. I think I came back far more drained than when I went away!
I also feel guilty comparing my pregnancy this time round with being pregnant with DS. I really feel like I am shortchanging the new baby as I am constantly knackered and running around, I am not eating very well (I can't stomach vegetables except tomatoes , and I hardly ever think about the fact that I am pregnant (except in a resentful way when I have my head down the loo!)
By this time with DS I felt totally centred and really bonded with the baby, was eating healthily, resting up etc. This time round I find it quite hard to even remember that there will be a number 2 on the way shortly!
But please, please don't add to your stress by worrying about the effect on your new baby - your body is amazingly resilient and let's face it, if stress and grumpiness could affect the baby then I am sure all 2nd children (and the majority of 1st babies!) would be little shrimps.
Can you get a friend to take your DS for an hour or two in teh day so you can nap? On the days I am at home I have recently upped my DS's daytime nap to 2 hours (for totally selfish reasons - so I can get a nap too) and it's saving my sanity, honestly.