I am also a teacher. After I had dd, i went back when she was 11 months and only did 3 days a week. As soon as she got to about 2, 2 1/2, and life was a bit more manageable, I started getting my act together work wise. Eg took on another TLR, brought a bit more work home of an evening (which had not really been able to with a baby). I just really worked at being a great 3 day-a-weeker, which is hard, as you aren;t in the loop as much.
When she started Reception, I went back up to full-time. I am now top of scale, post threshold, TLR 1. It was hard, but am now not class based anymore, so that frees up my evenings and weekends as I don;t have extra work to do as often.
I quite regularly used to take dd in during the holiday and make her watch DVDs and eat a packed lunch, so I could do extra planning/paperwork/sorting etc. Bit rubbish for her, but it meant SMT took me more seriously that I was not planning to try for promotions and then not commit. Now she has just finished Y1 and it has got a lot easier all round.
Apologies for the essay! But, it is doable, it is just hard work while you are doing it. Plus, I am not only mum, I am the emergency contact - I have no one for childcare at all, so had to do all of it.