Just reading your post, I'm not sure about several things. Did your doctor recommend this eating plan, or does he/she at least know you are on it? I ask because the book recommends that teenagers start in phase 2 if they're going to do SBD at all. Also, based on your weight and height, it doesn't seem to me that you're overweight.
Second, I can't tell what you are eating, but it doesn't sound like the usual SBD menu. Are you eating lots of vegetables? If you posted a sample menu, someone might be able to give you some suggestions.
Also, fluctuations in weight are very normal for everyone. A person's weight on the scale changes for all kinds of reasons, even over the course of one day. I don't know anything about what would cause bloating. Trying to control your weight within fractions of a pound will always lead to frustration.
Be sure you are talking with your doctor about your eating plans. He or she really knows you best and can give you specific advice that's right for you. I hope that helps!