I was told that I would be too busy with the baby to take extra responsibilities

I work at a school which is very male – rugby orientated and still resides in the dark ages.
Whilst on maternity leave a promotion came up at work within my department for head of Personal Social Health and Moral Education (PSHME). I had been asked to write the PSHME programme during the last few months of my pregnancy and believed it would lead to this position eventually. I found out when I returned from maternity leave that the post had been given to a younger member of staff, early in their teaching career to placate them for not getting another senior role. I wasn’t even told the position was available. When I enquired about why I wasn’t even considered, I was told that I would be too busy with the baby to take extra responsibilities. However they still used my scheme of work!
I was also told by the school bursar that women teachers were a financial headache and he wasn’t going to employ anyone again who had just got married as they take advantage and get pregnant to claim maternity pay.
When my children contracted chicken pox at 3 yrs and 1 1/2 yrs old, I was told to bring them into school to sit in a room by themselves so I could still teach (which I refused to do). I was also told that I should get a nanny as It was ridiculous that I would expect others to cover for me whilst they were ill. I was shouted at for 30 minutes, told I was a bad parent and that the other staff hated me for taking time off work.