Some timea i feel like everything around me are not real i feel as i am dreaming , this sensation sometimes stay up to weeks and i can't concentrate ?!

Need assessment: Many things can cause symptoms like this -- like drug use/intoxication, head injuries, psychosis, trauma responses w/dissociation, etc. Full evaluation requires in-person doctor visits. To get help you can start with your primary care physician, who can review your overall health & get appropriate studies. Your doctor will likely also want a psychiatrist involved in your assessment & care.