It seems hopeless

I don't even know yet what is wrong with my knee. I won't know anything till the 22nd. An MRI shows the fluid on my knee. I went today to buy a brace for it. And the knee is so swollen I cannot find a brace big enough to fit it. I am scheduled to put in 40 hours of overtime in the coming week. I don't need to be hobbled. I need to be part of the solution not the problem. I am afraid that I will need surgery. If I do it will be at the worst possible time. There are already two vacancies in my work group. If I am out of commission that would make three. Right now I am pretty disgusted with myself. I need to be available for more overtime. I don't need to be creating it. I wish my mind would stop. My stupid inner voice keeps telling me it will be the worst this time. That voice keeps telling me I will need a knee replacement. I am getting more depressed just witing this. I need for things to just stop for a while. I need to get outside of my head and my negative thinking. But everytime I try the reality of my knee and the pain I am in knocks me back down. I don't want to give up.