My leg just collapsed on me today.

Got out of the bed and immediately my entire leg just collapses. I fall to the ground, and can't feel anything from Lower leg to my waist. I'm relatively okay now, but there is still pain a few hours later. It changes from a level of 3 to 7 or 8 on the pain rating. Did I sprain my knee? I kind of slumped to the ground and it bended backwards. I didn't hear a pop noise but I started holding my breath when I fell.

Going to the doctors tomorrow morning. But am curious as to what could have possibly happened. There was some slight tingling and pain just above my ankle and in my small toe before it happened.

23 years old male mostly healthy. Non smoker and don't drink or do drugs.

I would suspect that you slept in a position which had blood circulation partially cut off to the leg. That would explain the tingling and the lack of muscle action when you attempted to stand up.

Looks like there's swelling and a rash in the ankle. Wasn't able to get to the Drs today. Going tomorrow instead.

This exact thing happened to me a month ago. Don't worry man, it'll fade away around one to two week's time. anderj101 is right, you probably slept in a bad position, cut off circulation, and maybe even pinched some nerves. I couldn't get my leg to support my weight at all, nor feel it. As I regained feeling and capability, that numbness and weakness was replaced with pain and soreness, like I overworked out doing leg day all day erry. I thought I might've needed to see a doctor too, but surprisingly when I called my parents and told them about it, they didn't even think it was a big deal at all (and they usually going to see a doctor for every little old thing, at least my mom). So yeah man, hope it gets better soon, it should!