How do i help cure my dog from fears of random household objects?

I have a 6-month old Olde English Bulldogge. I bought her from a very caring private breeder when she was 8 weeks old. She is a very happy, well-adjusted, affectionate dog but she is EXTREMELY WARY of random objects. The opening of a grocery bag, the sudden rustle of paper, our fake Christmas tree, anything falling and making a loud noise- practically anything that is new to her or anything that may make an unexpected movement or noise. I am an umeployed, recent college- so we spend all day together and she gets plenty of attention and when she gets spooked- she runs to me or hides in my room until I go to ure her that she is okay. We have gone through a puppy obedience cl and she loves interacting with people and other dogs and I try to couple new experiences/things with positive reinforcement and most importantly- I am almost positive that she has never had any bad encounters with abuse or neglect. When I picked her from her litter-mates, I did notice that a couple of the others were larger and more boisterous and she was more quiet and calm- but now she is a pretty hefty dog and is scared of something as small as a roll of paper-towels. Does anyone have any similar experiences or perhaps any tips on helping her to not be so easily scared? Any advice will be greatly appreciated.