12wks, problems with prenatals?

I didnt have any problem with taking them until 8wks when i started feeling sick. My morning sickness has eased up A LOT (thank.god) but my pre natals still make me puke, violently. I dont get nauseous, i will even forgot i have taken them. ALWAYS about a half hour after taking them the urge to puke hits me like you wouldnt believe. like no feeling sick, no warning. just BOOM! puke. cant make it to the toilet or trash at all it is so pushy and i dont get hot and sweaty like i do with my morning sickness. im wondering if my body just cant handle the sudden surplus of vitamins? it doesnt matter when i take them either. ive been taking them before bed and yes i will go in to a nice deep sleep and wake up to immediately puking on the floor next to the bed. im taking One A Day prenatals and DHA/EPA supplements. any advice from someone who suffered the same? i do plan on asking my dr but im just looking to relate at this point. thank you! :) <3