Q&A: How much I should be eating to meet my caloric and prenatal vitamin needs?

I have two questions for you. The first regards my diet and the amount of food that my doctor says I should consume. I am trying to take everything that I eat or drink into consideration, to make sure that it is something helpful and not "empty food" but as far as I can tell I am only getting about half of what my doctors want me to. Not being a good eater in the first place, coupled with feeling sick much of the time has made this very challenging. My second question concerns prenatal vitamins. The vitamins containing iron tend to make trips to the restroom very uncomfortable. I just can't seem to take any of the vitamins that my doctor has suggested without suffering this discomfort. At this point he's recommending that I use a prescription, as opposed to an over-the-counter variety. Another issue concerning vitamins is that I have always had difficulty swallowing pills. The queasy stomach compounds that problem. I gag horribly, even on pills I would normally have swallowed without a problem. The multi-vitamin is getting increasingly difficult to swallow. I know that if I become too inconsistent in taking it, it won't be doing me much good at all. I am really frustrated and know that I would feel better if I could get some of this smoothed out. Can you give me any advice on how to do so?