You are not horrible, not matter what you decide.
You've tons of mixed feelings about lots of different things. BFing is an emotional thing in any case and sounds a bit like DH is putting a bit of pressure on you, which can't help.
On the diet side: I'm vegetarian and have had to give up dairy, I also avoid soy.
I've had to reintroduce fish and that's made a difference to me.
I have a really fast metabolism and I found I just have to eat *more* or I feel like a wet dish-cloth. These days I have breakfast, a snack with LOs, lunch, another snack, dinner with LOs and a sort of second dinner later.
Can you add nut butters into your diet? The classic peanut butter on a bagel is an excellent energy-giving snack. Banana + pb "milk" shake is a great filler as well. Almond butter is divine with slices of apple. Fish? Great for protein and handy for quick lunches. Hummus. Avocadoes are my best friends, chopped or smushed. Go back on the chocolate! Try making hot choc with your almond milk - very yummy. When the dairy restriction kicked in (and it's me, for life, not her, sadly), I started baking a whole lot more. I eat more cake now than I ever did before (lucky me) but healthy-ish kinds that are also good for the LOs. Apart from the brownies I hide from them.
I'm sure Ali will set me straight if I'm wrong but I don't think Violet's doing anything out of the ordinary. She will very soon get into solid foods and life will change immensely by the time she's one.
Not matter what you decide, you'll be doing the right thing. Just make it the right thing for you. (())