I think you can relax about getting a fracture. With a score of
-1, you have mild osteopenia, and yes, I believe 5 months may be a long enough period of time to show significant changes.
But again, with all of your issues, IBS, lack of menses, etc it may be a long journey requiring much commitment on your part.
Along with your dietary changes, and walking, I highly recommend weight training. Did you know that as a person gains weight, the bones adapt to the extra weight by building denser bones? If lifting weights does not appeal to you, get those weights that velcro on to your wrists and ankles and wear them around the house and on your walks. Put on your favorite music and dance!
My mother-in-law did this for a day in the house and was stiff and sore the next day so start slow!!