Try to take your prenatal every day and eat whatever you can stomach right now. You still have plenty of vitamin stores left from before you conceived. These will last for much longer unless you already had a deficiency. My biggest piece of advice is that if you can't keep a whole prenatal down, try just taking folate (or folinic or folic acid. It's the same thing, but folinic is more easily used by the body than folate which is more easily used than folic acid) and vitamin D. I take a prenatal about 5 days a week and take a very high dose (10,000) of vitamin D each week along with methyl folinic.