This probably isn't a side effect , but when a medicine like Tylenol or Zyrtec makes you sleepy, does it make you feel like very "relaxed" .. I was getting ready to go to sleep, and for a few seconds I almost felt like I could feel my whole body. Like when your in a deep sleep. It was weird. Is it because it makes you really really drowsy orrrr? Was I just thinking about it to hard lol. I know I sound stupid