Pregnancy problems...

Please tell me I'm not the only one who couldnt keep my prenatals down after the 16 week mark. I can't keep those down, or children's vitamins...really any vitamins but baby is moving around and still has a stong heartbeat. My OB said when I go in the 28th I might be able to figure something out, but I can't seem to keep just those things down. My Midwife even told me that I don't HAVE to have any of them after reaching almost 5 months. But, I didn't know if I should be worried about my baby's health, or if my baby is going to be okay.?