Child support...help!

Please help! How does child support work where you're from?! My ex husband and I just recently went to court where, despite evidence of him not being able to financially care for our 2 kids and putting them in danger, the judge awarded him joint residential responsibility. Previously I had primary and so he had to pay me child support. They now (the judge and my ex husband) want me to pay him child support using my nursing income. It will be 3 years this March since I've worked as a nurse (quit that to open a home daycare to be home with my kids more), but he's claiming that I knew back in 2018 that he was going to go for joint responsibility so that's why I quit. To get out of paying him. I quit my nursing job in March 2019. Nothing with court started until the spring of 2021...after I told him I had lawyer. So I guess I'm just magically supposed to read his mind and know that he might want to do things in the future and let that dictate my life.

They are also saying that since we are in the middle of a pandemic, I should have no problem going out and finding a nursing job. So they are wanting to force me into a job so that I make more money to pay him. They are wanting me to pay like I am making almost $40,000 more a year than what I make now. My lawyer says it is not legal for the judge to do that, so if she sides with him, then he said appeals will happen. I was not ordered to pay him child support when I quit working as a nurse, so I had every right to do that, but he's claiming that I should've had to pay him. It's just all so crazy. How do they expect me to pay that much in child support (over $1000 per month) when I haven't even made close to that in almost 3 years?!

It's like this judge wants to punish me for doing something that was better for myself and for my kids..and now I'm paying for it..3 years later.