On a physical level, sugar is often less a problem than other sensitivities. I was tested for chemical reactions, often in groups that included children, and would watch them transform from calm/cheerful to angry/weeping/hysterical just minutes after tiny amounts of different chemicals were squirted under their tongues.
And I have noticeable mood swings myself (as well as a whole list of physical miseries) when I've been exposed to perfumes and scented products, air fresheners, fabric softeners, pretty much anything that gives off fumes, food additives (colors and preservatives). So it might be worth more investigation in that direction.
If those aren't problems, it sounds like communication could be. You may need to seriously work with your daughter on expressing her needs. If she's not very verbal yet, give her pictures or hand signs to communicate with, and to whatever degree possible, honor her requests, or at least acknowledge what she's asking for. Empathize with her wishes, even if you can't fulfill them. Tell her why not, or when you will get to her wishes.
And do everything you can to be sure she's getting enough sleep, and that low blood sugar isn't triggering these episodes.
This situation won't be solved easily or quickly, M.. Please do remember that your daughter is not trying to make your life miserable. She's expressing her own discomfort or unhappiness, and she needs you to be her advocate.