Oh no Betsi! I hope everything turns out OK with NO NO NO surgery. I did a similar thing once - really stupid. I was visiting a friend in California and there was a step down into the den. I was not paying attention and stepped off the step and hyperextended my knee.
I thought I was going to die. It hurt so bad. I limped around the rest of the visit and had to go to the doctor when I got home. Thankfully, it healed on its own, but the knee has never been the same. The bad thing is that it was my good knee. I blew out my ACL in the other knee playing basketball in HS. Back then, they did not graft ACL's so I just don't have one, which makes that knee really loose and unstable.
I'm resigned to having at least one, if not two knee replacements in my future.