i had this problem too when i was pregnant,
i couldnt keep water down at times or any small meal down.
my doctor told me that even though we throw up when pregnant-some people dont at all LUCKY!- you really aren't throwing EVERYTHING up, the baby still gets nutrients and also, if you are taking prenatals that helps with assuring that the baby gets everything he or she needs.
Do you take your prenatal vitamin in the morning?
I always got sick all morning when i took them when it was morning, so i would take them in the afternoon time, i found i did not feel sick when i did that.
but i had morning, afternoon and night sickness for 3-4ish months during the beginning of my pregnancy all the time.
after 4 months or so, i had morning sickness and sometimes got sick at night, then gradually near the end of my pregnancy i had sickness one or two times a week.
You should talk to your doctor about this, and see what his or her response to your question about this is,he or she can also determine if you are dehydrated too.
there are medications you can take to help with morning sickness..i never took them, i stayed away from meds while pregnant other than my prenatal vitamin.
i just toughed it out and ate crackers in the morning time or dry toast, sipped at water and guess what, even though i was still having sickness around the clock, i was still gaining weight while pregnant, and my doctor assured me i was not dehydrated and that the baby was perfectly fine.
good luck hun, things will get better though.