If none of that work, you can try unisom with vitamin b12. If that still doesn't work, ask your Dr about reglan or zofran. That's all that worked for me.
Have crackers by your bed, get some ginger ale, gatorade and peppermints helped me out. :)
And I almost forgot, some prenatal vitamins cause nausea in women, so it might help you to take them at night, that way you can sleep through it.
Avoid greasy or fatty foods. Avoid laying down within thirty minutes of eating. Eat smaller meals, more often then before (I used to eat three meals a day with one snack I'm between each, now I eat a small meal every 2-3 hours and a snack or two) the reason I'm saying that is because it evens out your bodys levels, I find that if I let myself get hungry I will throw up the food I eat, so I basically always have to have something in my stomach. When you wake up in the night to use the washroom, eat a couple crackers or a piece of bread and it should make getting out of bed in the morning easier. Wear light clothing, heat is also one of my biggest kickstarters for nausea. Drink plenty of water, but avoid drinking too much juice because that can have the opposite effect. Suck on mints or sour candies, I find that sometimes just having a little sugar calms my nausea down. And most importantly, if you crave something, eat it! Because it is something that your body wants, you have less chance of your body rejecting it and throwing it up. Oh and one other thing, my doctor said that food only has to be in the stomach for twenty minutes in order to digest the nutrients, so if you can, try to wait twenty minutes before vomiting, because then your body absorbs what it needs.