is this normal

so lately I have been having stomach pains, I also feel nauseous, and dizzy in my 1st class at school. usually I pass it if as I am tired or hungry. And I can't be pregnant because I had my period. today I was sitting and talking to my step mom and I felt a lot of discomfort and pain in my back, I have muscle spasms in my back, so again I ignored it, then I felt really dizzy and my ears started to ring, my step mom was saying stuff but I could not hear I only herd the ringing. I am extremely scared because I am only 14 so I should not be having any major problems like that. can some one please give me suggestions.