I feel sick every morning. What's wrong with me?

This has been going on for about 4 months and it happened once last year. In the morning i feel like im going to throw up, and i feel really weak. Its only whn i go to school. And i thought it was because i dont eat in the morning, but i do. I eat everymorning, but i only feel sick on school days. It lasts for about 45 mins. If anyone knows what this might be can you please help me.