Hi i am 22 weeks pregnant & have been taking doctor prescribed prenatal called prima care tablets?

but i think those tablets are strong & incresing my acidity & nausea.so i asked my doctor if i can buy other tablets like the ones we get at costco store,where they come cheap & in big quantity.she said its fine but i still wanted to confirm with u all.it has Corn, Fish (Anchovy, Mackerel, Sardine, Skipjack, Tuna), Soy as ingrediants.is it fine for baby.the name of the tablet is PURE GELS prenatal multi.can u advice me.i am planning to get my prenatal so pls help