I woke up, had my eyes open, but was unable to move. Is that sleep paralysis?
Very likley. Sleep paralysis is the inability to move any voluntary muscle at when falling asleep or from awakening (e.g., from REM sleep) while being subjectively awake and conscious (eyes open and aware of one’s surroundings). Episodes, which can be exceedingly frightening, may last a few minutes and subside either spontaneously or when interrupted by noise or other external stimuli. Sleep paralysis is often accompanied by fear, hypnagogic hallucinations, and intense feelings of realism.