I am a fit and well 50 years young mum of 3 (youngest is

Following x-Rays and a CT they told me I had a "well defined mass in the pancreatic head and uncinate process measures 45 x 35mm with central enhancing solid mass and surrounding cystic component with peripheral dystrophic calcification". They also mentioned gross dilation of the pancreatic duct and differential diagnosis IPMT vs mucinous cystadenocarcinoma.
At this point it seemed that I was being told I had a cancerous tumour, but also advised that because it was so close to the major vein. Pretty devastating, and a lot to take in.
However I was referred to a specialist and had an endoscopy and fine needle, and another CT. He tells me that the latest CT and endoscopy show less inflammation and he proposes a whipple (PPPD) surgery. The biopsy he says was inconclusive. I know the surgery is a huge undertaking but something rather than nothing which is what seemed to be the case initially.
I am an optimistic realist and so have taken on board everything, and come to terms with the situation, and been busy organising practical matters. The emotional side is a different matter, I live alone and have only an elderly father who doesn't love locally so I am just 'getting on with it', though friends are very kind. However everyone always wants to know detail and I don't have anything more than I have already said.
One other query/point that relates to this is whether this is still (or whether it ever was) cancer?
My work have been very good about my time off, but thought maybe I had inoperable cancer, now there is an operation available they want to know what that means in terms of my employment and possible return.
I have a critical illness form which asks me to tick either Cancer - excluding less advanced cases; Cancer - second and subsequent or Terminal illness, do any apply?
Hopefully future posts will be shorter, but I am just trying to get my head round everything and still deal with the day to day! Any help gratefully received.