Oh dear, I am very sorry to hear this. None of this is your fault. Your parents are screwing with your head by fighting with each other but using you as a proxy.
That’s just disgusting IMHO, because it inverts the parent-child relationship. They are acting like screaming toddlers, which has thrown you into the caretaker role. This is crazy making and I think it’s perfectly healthy to be exhausted, frustrated, and sad, because you are in a fcked up situation. Although it is not your fault, it may be up to you to extract yourself from the situation. I could make some suggestions if you want, but I also respect your ability to find out what works for you.