This was happening to me, and I was even fainting when I got up from bed, and they checked my vitals and my sodium levels were really low. They put me on salt tablets for about 1 year and I felt SO much better. Gradually I went off them and my levels have normalized. I like salt so I still put plenty on my food, but I don’t need to take the tabs anymore.
So, basically your body will produce the breastmilk that your Bub needs whether you eat the correct thing or not. The only person that is worst off in this part is you. Your body will sacrifice what it needs to make the best milk it can for baby. So please don’t worry, sounds like you need high protein/high calorie diet anyway, producing breast milk takes an extra 500-600 calories of energy. please don’t stress. it would make more sense that if you were giving your Bub lots of sugary things to eat that you would affect their cognitive development.