Breast Pump Advice Needed Please

I'm a first time Mum and need some breast pump advice please! I have severe osteoperosis (not pregnancy related, have had it since my early twenties) and because of my low bone density, I have been adviced by specialists that it's only safe for me to breast feed for a few months otherwise I will lose too much bone density.  They've said most definitely no longer than 6 months. To be safe I may only do it for 3-4 months as I can't care for the baby if I have broken bones.

Because of this, do you think it's still worth me investing in a breast pump? I know they can be quite expensive so I'm just not sure if I'd get the use from it. Also, I will be a stay at home Mum and so what situations would I use one in? 

Thanks everyone for your advice xx