A few years ago I went to ER with what I thought was appendicitis. They x-rayed me and found no appendicitis, but did find a large tumor on my left kidney. I had to have the kidney removed and have been fine ever since. Yes, I was scared to death and worried if it was cancer and had spread. Luckily it was cancer but not spread beyond the kidney. My main point is, I have been suicidal many times and thought I really wanted to check out. But when it came right down to it, I discovered I would do whatever it took to keep living and would go thru whatever treatment I had to to keep living.

Worrying helps nothing and usually things are not as bad as you imagine they are. BTW, your whole body probably won't be put into the MRI machine if it is your knee. But, whatever they find can be dealt with.