I certainly understand your rush to get better, Bearsmom. I was the same way. Please give the two week plan a full go of it, then try adding back in one food at a time. I was very strict with the FP points, even trying to make meals for the day that kept the points as low as possible (I did not do the desserts, unless it was just the simple fruit cup with some cream). After the two weeks, I would eat a little of one type of food (such as full lactose milk, not a problem but I am guessing I have the lactose-digesting gene due to ancestry). Then a week or so later, try another food. Higher FP fruits seem to be okay, so I don’t think fructose is a problem for me either. What got me every time were potatoes or if I ate too much bread (or even a little whole grain bread) or anything starchy. I would know, because I would start burping like crazy again and my LPR symptoms came back. So then back off of those things for a while, and try again. Norm says in his book, and it was the same for me, that as your digestive system heals and the gut flora re-balances, you may find you can increase tolerances for foods (but need to know your limits). I now eat dark chocolate, and have even tolerated small amounts of potato.
I like to think of the process of re-balancing the gut flora as a football game. There are two teams (the SIBO and the Good Guys). As one team starts winning, the other will change strategies and make a comeback, and then the first team changes strategies, etc. So, I did have some setbacks just as if the SIBO was making a last stand, but after a few months everything balanced out.
So to answer your questions about the Mag, if you are only on the first week of the FTD diet, it is hard to say if it is causing your issues.