Interestingly, thunder and fireworks are actually the only 2 things you CANNOT desensitize a dog to. The reason being, with thunder- they can actually feel the electricity, and fireworks- they are too random.

Id just try your best to keep her calm and secure. Maybe put her in a quiet room, in her crate, covered, and turn on some classical music or tv. Maybe try giving her super special treats or a really good stuffed kong or bone to occupy her, however usually when dogs are in such an emotional state as that they wont eat. The other option is to ask your vet for some acepromazine to keep on hand to tranquilize her. They kick in quick and last all day.