Aw don't feel guilty. It will do him good to keep going, a change in routine now right before baby will confuse him. He will be ok like you said (my mum works in a nursery and gets the mums to 'peek' through the window after they have left - to see their LO playing happily when seconds earlier they'd been inconsolable)
I used to feel the same with DD. She hasnt been for a while, had to take her out last year as was made redundant. Started my own business but can't afford to put her back in yet. She is back in sept for pre-school. Will feel awful dropping her off and leaving with DD2 to go home. Don't know what she's going to think about that
Feel bad on her today, I have NO patience and I'm in agony (had a fall yest ended up in L&D all is ok with bump I'm just very very sore) Poor thing she doesn't understand why mummy's being boring.