Clock, I am not one to take a lot of medications, but I have been down this road. I was diagnosed with osteopeinia when I was in my mid forties. I tried the diet, weight training, calcium plus D supplements, nasal spray made from salmon bones, and Evista (a hormonal treatment for osteoporosis). Despite 25 years of impact exercise, I was diagnosed with osteoporosis last year, at age 55. I had tried the medications you are referring to (in pill form) about twelve years ago and had the terrible gastric side effects. So this year, I tried the Reclast infusion, which is basically the medication you are talking about, but it is given once a year in an IV, for 30 minutes. It by-passes the gastric system, so it doesn't have those side effects. Yes, there are other side effects, but at this point, the fear of breaking my hip from a bike crash or other sport I do is enough for me to want to try to stop my bone loss with drugs. Nothing else has worked. I saw both my grandmother and mother lose inches from this disease. My grandmother broke her hip and she was never the same.
Anything you read on the Internet is not going to be positive... I stopped looking at that stuff a long time ago. I am not about to stop all of the activity I do; I decided to stop mountain biking because of this, and while it's not a sport I was great at, it kind of pissed me off.
It's quite possible that your broken back may have had something to do with the state of your bone density. And yes, I read the study about calcium related to heart attacks, but if I remember, it was a pretty specific population that was in the study. I would absolutely not stop taking calcium/vitamin D/magnesium, along with dietary changes.