I learned many years ago, both on my own and from the doctor at the Cleveland Clinic, Dr. Eversman, who I am sure has passed away by now, that taking in protein lasts longer than a candy bar. A candy bar is quick sugar that will bring you back in 10-15 and then as time goes on, I would feel even better minutes, but protein, which eventually turns into sugar will last longer. So, in the morning, I have different things, sometimes oranges and bananas, sometimes eggs, sometimes sugar coated cereal and so on. I also make sure to eat lunch, even if it is a light lunch, but not just empty calories, like I may have a PB&J sandwich, egg sandwich, cheese and cracker and so on again. I especially like the Laughing Cow small spreadable cheese on Townhouse crackers. Maybe a small salad, or anything that 'slowly' turns into protein. It's really all about duet.
I once had an attack (age 20) that I thought that I was dying. All of a sudden my whole body just went limp and I had no use of anything. I was limp, sweating profusely and shaking like a leaf on a tree in high wind. I made it to the kitchen and poured myself a huge bowl of Rice Crispies with plenty of sugar on it. After 15 minutes or so, I started coming back. But, like you, I wasn't worth crap most of the rest of the day. That was my worse day ever.