Some dogs are terrified of loud noises. Some will even do great harm to themselves just to get away from the noises. I saw a story on animal planet about a dog that went thru a window to get away, she almost bleed out from the cuts the glass made. I would contact my vet and see if they can give her a seditive to clam her on the 4th. You may also want to move the fireworks to another location. But make sure someone stays with your dog.
KC is terrified of loud noises. Faeden, on the other hand, could not care less. Everytime we have a thunderstorm, she becomes velcro dog. She will even urinate on the floor at times. I would think that your dog's reaction would be normal.
A lot of dogs are afraid of fireworks (the loud noise). That's why it's always reccomended to make sure your animals are secure around the 4th of July because so many are afraid and will run and hide. I know a lot of people that give their dogs a sedative around that time too. Luckily Lacy doesn't seem to be afraid of fireworks. I even took her to watch fireworks with me the last couple years and she was just fine.
my dog Tammy isn't scared of loud noises like the other day there was a hail storm and she walked around the house like nothing was going on but i guess its because shes older and it doesn't bother her lol:D