Sorry you find yourself here. As the other guys have said, it's crushing blow - first the cancer and then the realisation of what the treatment brings.
As Ulsterman suggested, make sure you update your profile so people can provide appropriate responses. This is a great resource, the members are incredibly open about the challenges they have faced, and they are very supportive. The thing to do is get informed. Read the toolkit, read the many threads on here, research further afield, and ask questions.
There are positive stories, so don't think it's all doom and gloom.
Good luck with the journey.