Well, looks like my knee is just fine, according to the X-Rays. And I apparently have very strong joints, so this manageable pain should be short term if I take care of correctly, which means babying it for a while (which I have been doing, and it is already feeling better), doing the correct leg exercises at the gym, and just letting it heal on its own before doing anything crazy with it.
And by right exercises, according to the doctor (who came highly recommended by several friends), doing any kind of leg exercises where your legs dangle is BAD for your knees. Which means I won't be doing these anymore:
https://www.exrx.net/WeightExercises/Quadriceps/LVLegExtensionH.htmlSounds like leg presses (commonly called the sled) and squats are the way to go. He said any leg exercises where there is resistance, as opposed to having your legs freely dangle, is the way to go. I am still very hesitant to ever do squats again, however.