Panic Stroke

About 20 years ago I was in my bedroom here in San Jose-Costa Rica, writing a letter to a girlfriend of mine, when I saw a black shadow just passing by the wall over my bed. I said to myself "ha, I've been visited by a ghost" and I continued writing. Some seconds later I began to feel really cold. I stood up from the bed where I was writing and I started to think that I was losing my mind. I was afraid I was going to forget who I was. I told myself to calm down , calm down. I felt a terrible fear, but I didn't really know of what I was afraid of. Then I called my Grandmother who was downstairs and I told her to call my Uncle who was a doctor. She went upstairs and when she saw me she said "Bryan what is going on, your eyes are red?". I then went to a mirror and yes,my eyes were completely red, like a piece of raw meat. I started to shake. I went to the patio and in my mind I saw a picture or image of the virgin Mary and for the first time in my life I prayed to her for help. I kept praying and praying and the all of my panic disappeared and also my red eyes and shaking.

That was my first and last experience of that kind. Years later I met a friend of The Theosophical Society and I told him about my terrible experience. He explained to me that I was visited by a vampire who "sucked" my psychic energy. Can someone give me another explanation

I'm a retired lawyer now. Interested in the occult, astrology and the supernatural in general