Healthy but high calorie foods

My doctor is a little concerned because I'm still losing weight at 32 weeks. She says that I'm probably not eating enough (as there's a ton of ketones in my urine as well). The problem is that I can't eat very much at a time anymore because my stomach is smooshed by baby boy. I can't even eat a whole burger anymore in one sitting. If I eat too much, I vomit. I will eat 5-6 large-ish snacks a day and I try to make them nutrient and calorie dense, but it just doesn't seem to be enough. Any ideas on some good foods to eat that will get me the calories I need and be nutritious enough that I'm not just eating crap? The only things I can think of are peanut butter half sandwiches, cheese, apples, nuts, and whole milk.