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Hello and thank you for your question. Your description sounds suspicious for possible seizures. Many of the things you describe can occur in someon ewho is having a partial seizure 1) shaking of an extremity 2) feeling sleepy afterwards 3)change in level of awareness.
I would very much suggest a visit to a neurologist who may do an MRI (to get a good look at the brain structures) and EEG (brainwave study). A common location for seizures is the temporal lobe and these two studies may help to evaluate this part of the brain as a possible cause of seizures.