Is it normal to be in bed and jerk cuz it feels like your falling

Lol! I totally thought you meant you masturbate whenever you feel like you're falling.

I've experienced this off and on as far back as I can remember, almost always accompanied by a very quick dream that I am falling from a height or missing a step & stumbling going down stairs.

There used to be a superstition that if you dreamt you were falling and didn't wake up before you landed, you'd die. I also remember coming across a theory decades ago that it's a vestige of memory from our tree-dwelling ancestors which stopped them plummeting to the earth in their sleep.

Anyway, my understanding is that it's so common it's normal

It's even worse when you're trying to go to sleep while high.

Hypnic jerk

The hypnic jerk may be a result of the muscles relaxing as the body goes to sleep. The brain misinterprets this as a sign of falling and signals our limbs to wake; hence the jerking legs or arms.

They say it's not fully understood but w/e it's normal

According to "supernatural" explanations (just to show you a different view ;) our souls sometimes leave our bodies (called astral projections, our of body experiences, among other things), and when we come back to our bodies, we "fall" into it resulting in that feeling.

That always happens to me... Then when it does I look around like someone saw me do it

It happens to me once in a while. I remember that, when I took perkosets, I had a really hard time to fall asleep because of that "hypnic jerk" thingamajig.

Occasionally I'll be drifting off to sleep, and I'll just spontaneously yell, not audible from another room, but plenty loud enough to wake me up completely. It's never an actual word, just basic sounds like "aah" or "eh".