Ive taken naps or slept and woke up feeling like this but it never scared me. I just felt spaced out until my mind and body fully woke up. when I was going through the diagnostic process for MS I was worried that this may be a symptom but both my medical and mental health treatment providers told me this happening to me was completely normal. short version some people require 8 hours of sleep per 24 hour cycle and others need more. when the body over sleeps or under sleeps its the brains normal reaction to make a person feel spacey/drugged feeling upon waking up.when someone sleeps the brain tells the body to release special chemicals. when a person under sleeps or over sleeps that chemical may still be actively slowing things down. my treatment providers gave me a great tip...they said some people need a little wake up call for their body's chemicals to return back to normal after napping/sleeping. for some people thats an alarm clock and waking up slowly before hopping out of bed, for others its a cup of coffee. with me its a pulsating shower that wakes this body/mind up.