joelle,

i'm sorry you're going thru this time right now.
i lost both my parents a few yrs ago and know what you're going thru.
it IS ok to think of yourself. it's a very stressful time and you need to look out for you while you minister to your family.

please consider getting a hospice organization involved with your family.
they are such a big source of comfort and info and support.
as long as you know the dx is terminal they can get involved months ahead.

i know it helped my family.
God Bless.
i'm sending prayers your way and your mom's way.