Hi powerpoint :)
If you body parts are numb, them you are almost near. I don't think it will hurt. Its hurts you because you feel it hurts.
Just don't think of it, lie down in a comfortable position, it helps.
Ya, we sleep soon when the oxygen to the brain is reduced.
So, while you are breathing half, which reduces the oxygen to you brain and make you body sleep soon. If you focus is good at this stage you can see your body goes to sleep and your mind is awake :)