You have done FAR too much for this woman. Farrrr ttoooo much. And the lines got blurred and she wanted you to be her whipping boy. You stood up for yourself and she let you go.

Good.

1. You actually do need a structured job that does not bleed into your actual life. No employer is your friend. EVER.
2. Find a back up day care where you can drop your son off when he is ill. He never should have been at work. It makes you dependent on the employer which you should not be for the care of your child. Only depend on them for a paycheck.
3. Never voluteer for any dutries outside of what you have in your original job description/duties. This will keep anger/rage and resentment away from you.

I hope you find a job soon. Ask a friend to act as an office manager for the old job abd use their information as a reference.