Prenatal a making morning sickness worse?

Kelsi
For a couple days I've been doing a lot of things and being very busy so for like 4 days I forgot to take my vitamin. And during those 4 days I felt great!! Afterwards I started taking them again and my morning sickness started up again so for an experiment I stopped taking them for like 2 days and no morning sickness!! I'm 13W3D now and don't know why my vitamins would be making me feel like that??