wondering if hospital should be an option now!

This is my first pregnancy and I am 12+1 at this point. I am on iron pills plus prenatals. Since yesterday I've been getting burning in my stomach and in the middle of my back, associated with sharp pains in my stomach. I'm not sure if maybe I'm constipated or somethings wrong. I called the doc, now I'm just waiting.  Does anyone know if this is normal or should I be on my way yo the hospital?  Thank you.