i believe your experience was caused by demonic attack. This phenomenon called "ALIEN ABDUCTION" as unbelievers people thought but in Christian's point of view this is called " Demonic attack". there's a website dedicated to all the people who have experienced the same as your's..in fact..their cases were much worse than yours..you're not alone as far as your experienced is concerned. these are demons pretended as aliens. there were some people who haven't accepted the Lord Jesus yet but when they used the name of JESUS in desperation during the abduction or the attack takes place...these alien/demons being have simply vanished. you are having this phenomenon because the demons had gain an entry in your life maybe in the past. it could be depression...witchcraft..quija board...watching sci-fi movies or alien from outer space kind of movies. Just seek a minister who had its expertise is DELIVERANCE MINISTRY. as for now...use the Name and the Blood of Jesus when they return...YOU have to completely surrender your past sins to the Lord Jesus otherwise they will return and harass you.
You can go to this website
http://wwwdotalienresistancedotorg/ce4.htm or u can type on google search engine >> "CE4 Research Group".
i guarantee they can help regarding your experience......Jesus is Lord !! God bless you