This might help: the vitamins (apart from folic acid and there's loads of that in bread and cereal) are not for the baby anyway. They're to support you.
I've had HG in both pregnancies but very badly with DS1. I lost 3st during the pregnancy and was hospitalised at 14 weeks due to dehydration. I couldn't keep water down let alone a massive pregnacare! I was very worried about the vitamins and so on. The amazing consultant in the hospital sat with me while I cried about it and told me not to worry even the tiniest bit about my baby, that they are little parasites and will take their nutrition from your body. They get their calcium from your bones and their vitamins from your vitamin stores. This, he told me, even includes folic acid, as the baby does not process food directly - you do that and they take from you. So, if you've been taking folic acid whilst ttc, or even if you haven't but you eat bread and cereal (which is fortified) then you will have some stocks I your system that the baby will take. It's your body that gets depleted and the vitamins are for you really.
If you're feeling sick, but can still eat, get some nice whole meal bread and have some plain toast, and a banana if you can manage it as your potassium levels may lower due to persistent vomiting and this can make you feel anxious.
And the pregnancy in which I became anaemic and lost 3st and ate literally nothing but oven chips and rocket lollies (I'm not even exaggerating - literally nothing else) resulted in a perfect, healthy 9lb 2oz DS who is a vegetable fanatic.
Please don't worry - its so easy to get sucked into all the you MUST have this pregnancy vitamin stuff - but if you ask your midwife she will probably say great, vitamins how lovely, but not look at all bothered if you're not taking or keeping them down for a few weeks. Toast, any veg you can manage, even a few raisins or whatever, and soon you'll be feeling better and will be able to keep the vitamins down.
Bless you - you sound really upset. The first trimester is rotten but it does improve, I promise :)