Worst pain in my life

Today in school my back was hurting so I went to the nurse and when I went up there my back was starting hurting me that bad that I was getting really hot, shaky and pale and it was making my mouth just water and was making me trow up,so they sent me home ..it was the worst pain in my life and now it keeps coming and going has anyone had this happen to them? Anyone no why this is happening ? I need help because I need to no of its serious or not