I cant stop eating ice?

ok i cant stop eating ice i been eating it like crazy for 4 years now almost 5 i can eat a big bag of ice from sonic in like a hour and want more if i go a hour or so with out it i feel sick and light headed what is wrong with me ice has become like a food to me and its starting to scared me bec now i crave it like most ppl crave a meal i need help but idk where to go plz help and thank you fro taking the time to read this even if you cant help god bless you