Last week, my mum was diagnosed with squamous cell carcinoma in her lung (I have been deliberately not googling it). 
It has spread to her windpipe and chest cavity (two lumps up near her shoulders) and is inoperable.
In two weeks she will begin chemo to hopefully give her a longer/better quality of life. Though they wont know how successful this will be until about Christmas.
I live about 200 miles away and have been travelling down for her appointments so that she is not alone and taking her out for lunches/shopping/afternoon teas while waiting. I also helped her break the news to the rest of the family.
I have remained positive and upbeat every time Im with her and then fallen apart on the train on the way home.
I asked if she wants me to come down and go chemo with her but she said no. She said that there will be times when she really needs me and so will call me then, but not to keep leaving my work/family to go to her, also she is trying to remain as independant as she can for now.
I just feel so lost. I want to do something, to help.
I know that a big part of this (selfishly), is because I need to feel like there is something I can do. That if I help enough or do enough then she will be OK. This chemo will work (It has to work, it has to. Thats the thing Im holding on to to keep me sane).

I am absolutely terrified, I just keep thinking it has to work, it is the only chance we have and it cannot fail, so again I have started waking in the night having what I can only describe as panic attacks at the idea of losing her.

I also panic about what if its worse than we thought? It has already spread into her chest cavity (2 lumps up near her shoulder), and last year she had quite a lot of pain in her legs and her GP said it was arthritis, but what if it is part of her cancer? Should that be looked at again to make sure or do I just say nothing in case they review it, decide it is part of her cancer and then say that its too bad/too far for any treatment.

I also realised last night that I have a friend who's father went through the same thing, and he responded well to the chemo but sadly passed away 18 months after being diagnosed (In a moment of madness I actually considered texting this friend to ask how she coped, but realised that could be more hurt/pain for her, and that would be selfish).

Its just so hard having to keep all this in (my mum only wants close family to know at this point), I feel so frightened.