Unknown disease. If you help me.

Hello doctor!! I'm 17 years old. When I fall ill my body becomes really weak and tired. I faint in a strange way...my body becomes stiff eyes remain open and I become unconscious for a few seconds. Few months ago I had vertigo attacks. While lying on bed when I turned on other side I used to feel like everything is moving round and round.When I was a kid I had some kind of neurological disorder, I always used to faint with body stiff and eyes open. My brain mri was done but it was all normal. I'm in class 12. After coming back from school I have no energy left, I'm unable to study or do anything else I just lie on bed and do nothing. My life is full of stress I'm unable to enjoy it because usually I'm ill with no energy. I just stay alone in my bed. I don't like to meet people or to talk to anyone. Please help me. Please suggest some ways... I would be really grateful if you help me.