Could it be cancer? HELP!!!!?

To try and cut a long story short, I was having seriously excruciating pains in my side so I had scans and it showed a tumour on my gall bladder! Since then I have been having scans 1s a month to check the rate of growth, the doctor told me it is growing at an abnormal rate and is now bigger than the gall bladder itself! I am having my gall bladder completely taken out next week so they can do a biopsy on the tumour! I am only 20 and soooo scared as I haven't even had an operation before! I also volunteer at my local marie curie cancer hospice and see young people dieing of cancer on a daily basis, I am soo scared and don't no what to do! Could this realy be cancer? It seems so surreal! Thankyou for reading xx