How do I fight a custody battle with my ex when I can't afford another attorney and he is well off? We weren't married.

We mediated through most of our issues last year, mainly because I couldn't afford to keep going to court with my attorney. I have primary physical custody.The judge told the attorneys to figure out child support based on our information. My ex threatened that he would fight this until he got exactly what he wanted regardless of cost. He is well aware of my financial situation. He basically told me that I could stop accruing expenses if I gave him what he wanted. We came to an agreement. It has proven to not been in my child's best interest. Recently, we had a dispute during an exchange and now he decided to change the amount of child support he is paying. I don't know whether the amount the attorneys came up with counts as a court order since the judge left that to them. What do I do?