My Dad Forced Me To Sign A Document Forcing Me To Pay My College Tuition

Right as I had finished high school, I enrolled to attend a local college. My father was against the idea, and wanted me to go to a school in Canada, which he had attended. Shortly after I turned 18, he took me out to dinner, cried, and guilt tripped me into signing a document, telling me he didn’t have enough money to help pay the tuition. The document stated that I was to pay all of the college loans that he was meant to pay off. He claimed that because of the million dollar house he had bought, he was struggling financially. The problem is that 4 years prior to this, my mom and him had gotten a divorce, which led to a messy series of trials and issues in court. Almost everything financially between them was discussed in court, one of which being my college tuition. He was specifically told by the court (in documentation as well) that he was required to pay half of my tuition. My mom isn’t even aware of the document he made me sign, because he begged me not too disclose it, and my mother is also terrified of court and spending more money on attorneys to fight him. My question is how much legal precedent does the document have? Does the court ruling over power it? I am still only a sophomore in college, so if not, how should I go about nullifying it? I realize I have made a lot of mistakes in this process, especially about withholding the information from my mother, but this weighs a heavy burden on me and I just want the whole situation to be resolved.

Additional context (feel free to ask me directly for details): The document he made me sign was written by his attorney. I received no copy of it, but I remember the general idea of it. He recorded me signing the document as proof.