Hi toHEornottoHE, yes, I was definitely depressed because she had gone to school. Weirdly, I was fine with my eldest, but she had been a really sociable toddler, quite a handful, and more than ready to start in that environment. My youngest is an end of August birthday, so was only just 4 years old. She had never settled in preschool (screamed solid for hours until the staff phoned us up, we eventually gave up) and she was adamant she didn't want to go to school. On top of that, from my point of view she was the easiest child you could possibly imagine. We would walk around the supermarket discussing vegetables while everyone elses child tantrummed in the sweet aisle (and I know it was nothing I did right because my eldest had been of the tantrum kind!). If you took her anywhere and said she had to sit quietly, she would. She was just the most amazing company, even at two. By four she was talking like a little adult, starting to read, spending bits of money in shops, enjoying lots of art, craft, having ballet lessons, going to church groups etc. I honestly couldn't see a single reason why she needed school.
When she started school it was just such a shock. I'd had this little person with me all day every day, and suddenly someone else had her and I had no choice. I hated her teacher, absolutely hated her. I felt guilty about it but it was beyond my control - I was so jealous that she got her all day and I didn't. I often wonder now if this was more of a natural instinctive thing than I gave credit for at the time. In the wild, animals defend their young to the death. Not many animals will let another mother take over.
It made it worse that the teacher kept on and on about what a wonderful child she was. After a couple of weeks they said she was so sensible she could stay all day. I absolutely refused and from that point on they had me down as some neurotic woman with separation issues! That first term, I don't know how I survived. I was so, so unhappy I could barely function. I hated the system for taking her away from me at 4 when, had she been a week younger (which she should have been, she was an early baby) she would have been a September baby and I'd have had a whole year longer before she started school. It seemed so unfair that neither I nor she had a choice.
Of course, now I know we did have a choice, but I didn't back then. And independence has happened gradually, from a real security, like you say. Forcing it didn't work. But the fact that she can stay with me 24 hours a day means that she doesn't have to, if that makes sense. My children have both gained more true independence since HE than they ever had at school. My experience is that, if you have a tendency towards depression, and you like the company of your children, you will be much less depressed with them around than with all the stresses school brings.