I Have Been Taking An Estrogen Blocker, Letrozole, Having Had

I have been taking an estrogen blocker, letrozole, having had breast cancer almost 4 yrs. ago. I have been told that this leaches calcium from the bones and I have been diagnosed with osteopenia and osteoporosis runs in the family. My nails are brittle and split but at the same time ripplely. I take a multivitamin for seniors, 1500 calcium and 5000 units of vitamin D plus 5000 of biotin. What else can I do? Wait it out until I no longer have to take the letrozole or femara which ends March 2017?