Getting nauseous and vomiting when drinking alcohol

Hi, I’ve been vomiting and getting nauseous every time i go drinking. I dont even drink much maybe like 4-5 5% alcohol drinks. But everytime after some time i get nauseous and sometimes even vomit. If i dont vomit there i sometimes vomit at my own bathroom when i get home. Idk what is the reason. Im 18 years old. If i remember correctly when i was 16 i drank clear spirit/liquor 40% mixed to sprite or coke and i didnt get nauseous or anything. What is the problem?