A.,
Every pregnancy is different. I have three sons and each time the pregnancy was completely different from how I felt, to how I looked, to how I carried, to how much weight I gained. With my first I was never sick. With my second, I was sick for the entire first trimester - every day, all day...in the second trimester I still experienced sickness, and in the 3rd, I was just exhausted the whole time. With my 3rd, I had a few rough mornings, but it was also the height of allergy season so it could have been that as well.
I could not take the pre-natal vitamins with any of them. Of course, not pregnant I cannot take multi-vitamins without getting sick either.
Bottom line is this...if your instinct tells you to go to the doctor and get checked out...go. If you think everything is fine and it is just morning/day sickness - keep doing what you are.
To quell morning/all day sick with my second, chocolate milk and a peanut butter sandwhich seemed to help...and I was never without gingerale:)
Hope the sickness ends soon for you so you can enjoy your pregnancy!
T.