MJ,
Boy, I can so identify with your feelings. I also talk about cancer a lot, because the truth of it is that our lives pretty much revolve around cancer these days. Every once in awhile I have my "cancer meltdowns" and I just let people know that's what's going on and have found them to be very supportive.
I look around at other people and am amazed that they have "normal" lives. I can't even imagine what it would feel like to have that again. However, I do know that the things they let bother them and tear them apart often look so ridiculous and petty to me. Don't misunderstand me. I would go back to our old lives in a heartbeat if it were offered, but I can recognize some of the incredible moments we have had together because of cancer.
Re. your mom's sleeping excessively. By all means, check it out, but don't panic. Steve slept most of the day for MONTHS after WBR. It is just in the last couple of months that there has been a big improvement. WBR just drains every last ounce of energy you have. Hang in there - your mom will come back to you. Just keep giving her your "special medicine" of love and support.