Huh, I just lived through this. My breasts went flat like pancakes and I was terrified that B wasn't getting anything. I just ate as much and drank as much as I could, and nursed on demand, and everything worked out fine. He's EBF, and so we didn't have any solids to fall back on. However, I did have about 6 ounces frozen, so he did get one bottle during that time, but for ~4 days, I was convinced that he wasn't getting anything. Interestingly, even though I took in about 1000 calories over 5 days, he still got what he needed from me and didn't nurse any more frequently than normal. So, try not to stress or worry (I think that made me sicker than I needed to be), our bodies are amazing, and your sweet one will get what he needs.
Oh, and eat anything you can - I spent 3 days eating bites of milkshake. Don't worry about what it is, or the nutritional content or anything. As long as it has calories, get it in ya!
Mama to H (6) B (3) : A (1)