I know this thread has run for many pages now, but I wanted to respond to first of all say - well done @wallypops3 for staying calm in the face of so many infuriating posts, and also, I get everything that you are saying.
It is really hard as a working parent, and let's face it, particularly as a working mother, when you have to deal with urgent family matters. You had no choice - you had to care for your child and you took leave to do so. On a practical level, I absolutely see that this is potentially inconvenient for your employer, and I get the stress / upset you will then feel when you pick up on your boss's ire. It's all just incompatible.
The comments about your DH are ridiculous, you explained the situation well - it made sense to make the choices you did, on another week, it would have been easier / possible for DH to pick up the slack. It wasn't, you had to - really not ideal for you but what could you do?
I have seen for years on MN this really irritating 'have a back-up', including mention of these (surely mythical?) agencies that will arrive, Mary Poppins or Nanny McPhee-like, to care for your sick offspring, with no notice.
It's true that some families have GP or family members close at hand who can step in - this is great. Some families, like yours, don't. Neither do I - I am a single parent, ex is essentially useless / uninvolved, no family close by and no friends that are in a position to help. My DC are now older, the issue is less pressing but I still have really difficult moments where my DC need me - and there's only me - and it impacts my work. I am lucky to have a good degree of flexibility and autonomy within my role but it is still stressful.
I just find it so annoying that so many MN'ers can not envisage different worlds to theirs - I can absolutely believe - and it sound great! - that there are 'it takes a village' communities, where it's so much easier to ask favours from obliging neighbours, where family members live locally and so on. A family member actually lives in a rural enough area, and has a large extended family, knows everyone in her community and as she runs her own business, was always popping out of work to pick up a second cousin or neigbour's kid from school and take them to her office for an hour or similar. She was amazed that I had to spend a fortune on breakfast club, lunchtime pickups, afterschool, summer camps and the like when my kids were small. But I did. So do many people. Swings and roundabouts, I'm sure - I'm sure there are advantages I have where I live and with my lifestyle that others might not.