I had a bone density scan after being on pred, and it wasn't great, but I was in my early 50s. I had osteoporosis, borderline, in some places. I started on Fosamax, a bone builder, but didn't like it. So I'm on my own...They should have taken a scan when you started as a baseline, but don't typically do it.
Then you need to make sure you are taking calcium. It won't rebuild but it will help you maintain what you have. At target you can get sweet candylike, calcium tabs. Take 1200 mg. a day.
Can you take the vitamins with food? Sorry you are feeling that way.
Maybe there is another chewable for you. You should get as much vitamins as you can from real food.
Sorry about
the proctitis (ugh). Feel better.