Injured knee, can you guess which?

I was scrubbing the floors in my house when I stood up suddenly and heard/felt a loud pop. When it popped my knee gave away and the pain made me cry and sit on the floor for a long time. I haven’t gone to the doctor because I was hopeful it was something that could possibly resolve in a couple of days. Unfortunately it’s gotten worse. The pain was on one side of my knee and now it radiates all over. I’ve been limping but when I get tired my whole knee gives away and I have to drag my leg, the pain also gets so bad it makes me cry. Can you tell which one is injured? I just want to know if it’s visible too. I’ve had injuries that I could feel but doctors couldn’t see so I felt like it wasn’t that serious. Could this be more serious? What could I have damaged?