I'd suggest you read all the info on the Royal Osteoporosis website- mases there- and they also have a nurse helpline so use it. (I think you have already?)
Presumably you are going to be referred to a rheumatologist?
This isn' t something where you're going to be left to sort it out yourself.
You will need to take one of the many drugs there are.
The most basic is a bisphosphonate taken daily as a tablet.
Other treatments include injections ( 6 monthly, daily or once a year.)
Your GP must send you to a specialist- from your posts it sounds as if this isn't in the plan?
I have a friend who has severe osteoporosis and I've been supporting her with her treatment for some years.
Yo u don't need to take calcium if you can get it from your diet- and that's quite easy to be honest. Three portions of dairy a day usually does it- milk, yoghurt, cheese - but also there's masses of calcium in tinned sardines, chick peas, salmon etc.
Taking calcium tablets is now not recommended as the calcium can harden the arteries and increase risks of heart disease.
You could also consider HRT as this is recommended as treatment for young women (under 60) either on its own or alongside the other drugs.
Exercise with weights will help- but you need to do the right ones. The NHS and the ROS has videos of exercises to help build bone in the spine, hip, etc.