When I was 10, I started experiencing fainting spells and a doctor told me that the only thing they could find was that I had borderline low blood sugar. To this day they can't find a reason for my black outs. I'm not sure what happens but if anyone has experienced anything like this, please share...

It first starts with my heart beating weird and hard, there's pain in my chest. Then it moves up my throat and to my face. I experience pain in my face and very suddenly I black out. When I black out it is painful in my face. It feels like my face is "asleep" and my tounge also. I have very vivid dreams while out. It only lasts several seconds, but it seems like longer and when I wake up sometimes I don't know where I am. People have told me that once my arm was moving uncontrollably and my eyes rolling. I was in a car once and my elbow kept hitting the window. I was in a pool once and I kept rolling around in the water. It happened once in the middle of the night and I came to with a gash on my head, not sure how it happened. The only good part is that I can feel when it's coming on, twice I was in a car but each time I had enough time to pull over. These started when I was 10 and happen maybe twice a year sometimes more (i'm 30). When the first one happened at 10 they took me to the er and ran an ekg and said no seizure activity was found. One time it happened immediately after I drank a milkshake, and i'm not sure if this has anything to do with eating too much sugar. They have no idea what's happening and have also tested my heart. Any ideas?