I worked until DD was 10mo. I just didn't get enough time with her and I felt like someone else was raising my child, so we decided I would quit.
Transitioning is hard. I worked in the computer industry with a lot of technical stuff and I generally worked closely with other people and did a lot of decision making and problem solving. It was quite a hard transition to go from constant interaction with others, stimulating (if stressful!) problems to solve and major decisions to make to looking at a nonverbal child all day long and seeing no one.
One thing we did that helped me was we did not drop the daycare completely - we sent my DD for a few hours two afternoons a week to the same daycare (it helped that this daycare was very small ~10 kids and she just loved it there). This gave me a bit of a breather while I got a chance to get my feet as a SAHM. After a while I didn't need it anymore, but she still goes because she loves her friends there so much! Now I'm facing a new transition - from one to two and I tell you I am scared!
The first month or two were great - it was like being on vacation. After that was when the hard transition hit, but after a few months of that I started getting into regular playgroups, finding a rhythm and things got a lot easier. It helped actually knowing what the alternative was (working) and that it wasn't acceptable to me, I think I was better off than if I had stayed home right away, always wondering what I was missing.
