This is a tricky situation. You need to work to support your kids but work is not support you.
Now this is only my opinion based on what I would do if you were me. I would start looking for another job that fits and is supportive. Having a great work community, that supports you just as much as you support it.
Once you found that job give a weeks notice and blow it up in their face. If it is so easy to say things like that to you, then perhaps you are not as valued. why stay there? What is being appreciated from you when you work there? Pros and cons. See it and then make the choice that best suits your needs.
It is not a good place to be, especially on your morals if it is only bringing you down. You do not want to be just a number on a piece of paper.
With all that being said, keep in mind I do not know your financial situations and capabilities and I do not know what your job is either.