Hi Nicole,
This is really frightening for you so may I suggest (as others may) the Cancer Council Helpline and also perhaps you might like to contact a social worker at the hospital where your husband is being treated.
Depending on how your husband feels about letting friends etc know about his condition, ask for help from friends, especially with your little boy. I found when I was on treatment even though my kids were teenagers, that real friends came out of the woodwork. Once they knew about my circumstances, I had people turn up with meals, do my housework and offer to drive me anywhere I needed a lift.
There is no easy way to deal with this but there are people who may be able to assist.
This site is also great if you just need to offload yourself.
No-one's emotions or experiences are more or less important than anyone else's.
Take care,
Samex