Big hugs Mrs D - I sympathise about you feeling bereft at leaving dd at Nursery. I had the same thing when my dd first started Day Nursery - I was in tears for the first week, but she was and is fine and has been going to Nursery for 18 months now (she is 2 years old). However with baby ds I was quite relaxed about leaving him (probably because I have been through it before).
Also Hewlettsdaughter - big hugs to you too. I can imagine it tugged at your heart strings when your ds clung to you limpet like at school this morning. Give him a week or two and chances are he wont give you a backwards glance!
I have had a lovely day today. Baby ds has been in Nursery (he attends Thursday and Friday, Thursday because it coincides with when his sister goes so I get a day free every week, and Friday so that I can have one to one time with his sister) so dd and I went to the zoo together....have concluded that 2 year olds are easier to look after than babies. At least they don't need lugging around every where you go. However love ds to bits of course, even though he is so full on and I can never put him down for more than 1 minute at a time.
Turned my back in the kitchen for a little while this evening, and when I looked around ds, who had been sitting in his bumbo seat, was wearing a potty on his head (courtesy of his sister). Moments like that remind you why you had kids.