hello im not sure about your problem however i would be asking myself if you are maybe experiencing minor seziures..there are a few forms of epileptic seizures and a friend of mine took them frequently and yet i never picked up on it as she just stared as if in deep concenration..i had to learn not shake her or attract her attention when taking one..
not alot of information and im here to advise so hope this is of some help too you.

This is defiantly something you'll want to see a doctor about. It could be a problem with you're brain. If it's a recent thing or something you have not suffered your whole life from, then it could be a tumor or brain injury.
If it's something you've suffered your whole life then it may be a brain defect or seizures, but regardless, it is something you'll want to talk to you're doctor about.