Prenatal vitamins making me feel uncomfortable??

Hey mummies, im 12 weeks 2 days pregnant and just started on my prenatal vitamins. Just 1day in i felt nauseated and I vomitted out my lunch ( fyi i didnt have super bad morning sickness during the rest of my pregnancy) . I had alot of gas in my body which lead to me farting alot, and i even had diarrhoea twice today… is this normal? Will my body get used to this? Or do i have some sort of allergy?