Was it a Dream or was it real???

It happened when I was doing my masters and I was staying as a paying guest for sometime. The incident still brings a chill to my body whenever I recollect it.

That night after having my dinner, I went to bed early since many of my friends were not there. The clock had not even struck 12' and I was not even fully asleep at that time. But I could feel the presence of somebody standing near the foot of my bed. When somehow I managed to gather some courage to take a peek at the foot of my bed I saw a figure dressed in white standing. But I couldnot make out the face since I was too scared to get up and have a look. Sometime later I felt somebody choking me and I was not even able to shout for help. After what seemed like an eternity the figure or whatever it was released me and vanished through the window. Then I got up from my bed and ran to the other room where my host stayed. I was not able to go back to the bed so I slept with my host that night. She tried to console me and put me to sleep finally.

It was one of my scariest experiences in life. I don't know whether what I saw that night was a ghost or not.