hi., These kind of experiences happen to all but if it very frequent you need professional help. First common cause is drug abuse. If you re using any drugs or certain long term medications can cause this. So stop taking illicit drugs. Contact your physician if taking any medicines. Certain seizures or epilepsy can present similarly. This will get relieved by medicines. Certain stressful situations can lead to these. So try handling stress properly or equip yourself with better coping skills by help of a psychologist. If you feel low, anxious with low energy and negative thoughts/worries, Depression or anxiety disorders could be a cause. Rarely these occur without any specific cause called as Depersonalisation-Derealisation disorder. Mediations like escitalopram fluvoxetine will help in all later cases. So Please visit a psychiatrist for proper diagnosis and treatment.