Anyone ever get oxygen deprivation while standing up?

Happened to me a few times when I first started.
SCARY shit.
Wake up with my knees bent, fighting for control of my body/limbs.
Everything shaking, fighting AS HARD AS I CAN to control my hands/bong, but I end up getting shit everywhere...

Couple times it's been pleasurable though. Taking a big grav bong.... and it's like stretching towards the darkness... and you get to a point of no-return...