What is wrong with me?

I am 12 years old, about to be 13. Here is the problem I am experiencing. In church and only in church I am experiencing some problems. It starts whenever I sit down in the pew after about 2 minutes, my head goes into a tremendous pain, indescribable. Then I start to go deaf and I lose my hearing at an alarming rate. I couldn't even hear the singing or prayers, they were only murmurs to me. My head is hot and it feels like it is going to explode. I zone out and my memory of what was going on around me is destroyed. My father said it looked like I was having and epileptic seizure because he said I was fighting to keep my head up, no I was not really tired. At the end of church I zoned out and I couldn't even see my parents leave, it was all back. Then I awoke to my senses and found people waiting to get out of the altar. THIS ONLY HAPPENS IN CHURCH. Is this serious? More importantly what is this?