Hi there and welcome.
I'm fairly new here myself, I can really relate to the fear you are experiencing. My husband started treatment on November 7th.
Some of the best advice I received early on was to not waste any time. My husband gained 19 pounds before he started treatment. I was able to get an appointment with our attorney to get things we'd talked about getting in order for years - in order. I ordered some things from Amazon before I needed them (cool mist humidifier, disposable puke bags, Jeans Cream (to deal with radiation skin issues) and I got some baskets together to store meds in so as not have our living area look 9 kinds of medical.
I'm sorry you are joining this club. It sucks on so many levels.
The people here will have some very valuable things to share.
Warm regards,