Hi @FionaJ the next few days will be a bit of a blur, it's a tough time in your life and noone volunteers for this ride.
I've had two bouts of BC, ten years apart, so I'd have been having my first treatment about the same time as your mum. Things have changed quite a bit since then. It's difficult when you have watched someone else's experience to not have a preconceived idea about how things will go and how you will manage your own treatment. The hard lesson is taking every day as it comes until you get a better idea about what your own personal situation is.
Hang in there, if you haven't already connected with a breast care nurse, the time spent in hospital is a good opportunity to do that. There is no point telling you not to be frightened, but if you are having straight mastectomy with no reconstruction, there is every chance the emotional trauma is worse than the physical and you may be surprised at how little pain there is and how quickly you recover. Best wishes. Mxx