? help dont know what this could be?

lately I been having pain in my lower back and stomach...the stomach pain has been the top part of my stomach like below my boobs. The back pain is in the lower part of my back. It feels like intense cramps in my back. The stomach pain is like a little bug. I been throwing up and pooping. I feel nauseous and had the shakes and a fever. I have a doctor's appointment soon but wanted to know if anyone has an ideas of what it could be?