Has anyone been prescribed FERROUS SULFATE??

I was recently prescribed ferrous sulfate 2 times a week because my ferritin is low, but it makes me so sick. The first time I took it I took it on an empty stomach as instructed but 10 mins later I threw up then today I took it 2 hours after dinner but omg I feel so nauseous and sick. Is it normal to feel sick after the pill & do the side effects get better? Or should I tell my ob to prescribe me something else?