A Demonic Vision?

I have had a couple experiences growing up with psychic experiences. Mainly astral projection and dreams coming true. I have however, never dealt with or experienced anything like I did today. I am not sure what to even classify it as and will try to explain it the best I can. I am asking for help to try to figure out what it might mean or at the very least some place I might be able to get some answers as to what it might be. Well here it goes: Today, while sitting at the doctors office, I suddenly got a wierd feeling and started "seeing" heat wave like lines everywhere around me. After about 15-20 seconds these lines changed. Some of the lines stayed the same but now there were suddenly "dots" moving back and forth between lines and other dots as well. I started to see green "flashes" (each one lasting a few seconds). With each of these "flashes" I saw a picture. First it appeared to be a head of a person I did not recognize. Then with each flash the image shifted a little until it was a head with rams horns. The face then shifted to an evil looking face with rams horns. After this transition the horns started to curl upon the face causing the face to disappear more with each flash and turned into a snake. This snake "lunged," for lack of a better word, at me while hissing and bearing its fangs. After the snake lunged it suddenly disappeared as quickly as it had started. With the disappearence of the images the green flashes stopped as well. Once the flashes stopped and the images were gone the odd feeling I had at first disappeared and I returned to feeling normal.

I have googled possible reasons or explanations for this but have had no such luck. I would like to deperately know what this might be and/or a possible meaning. Any thoughts?