Yes, it has happened to me and I understand your fear. It is the state I enter when I'm most dangerous to myself, because I quit caring and everything seemed surreal. Don't mean to scare you but keep aware of this state and report it to your doctor.
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Bipolar I, Depression, GAD Meds: Zoloft, Zyprexa, Ritalin
"Each morning we are born again. What we do today is what matters most." -Buddha