I was sleeping (my back to roof, tummy to bed, head turned left) then had numbness in my whole body I couldnt move, what is it? I'm afraid, I had anxiety

REM sleep. Its possible you woke up in rem sleep given that you didnt have trauma or other causative factors blink your eyes when you wake up feeling paralyzed you will snap out if it if it happens a lot get a sleep study with mslt again we are assuming other causes have been ruled out.