What Causes Stomach Aches And Headache, Dizziness With Fever And Cold?

well for the past week i have been having tummy ache, head ache , dizzy spells, having a fever on moment then felling really cold but not throwing up or anything like that. so why has this been going on for so long and whats the matter with me! ( 12 years old female mom said to look up online for help because she has not the clue what is happening)