Always Sad

It's hard to keep a "happy face" convincing after 20 years.
Mom asks what I do upstairs all day.
While I do anything she wants any time she wants, I feel like she thinks I do nothing (when in reality I am either crying, letting my "happy face" recharge, or trying to pass the time until she needs me again.)
I don't know how to keep a 78 year old woman entertained (when nothing entertains her.)
She asks me frequently what I plan to do with my stuff.
It's my stuff, I am selling my own place so I can't keep it there, what else am I supposed to do with it?
I feel like an intruder.
I am in severe pain all day, every day (and it's been getting worse due to an non-moving kidney stone, which I believe is now too big to come out and I fear for the inevitable hospital visit when it becomes too hard to "deal with".)
I lost my father, my home, my independence again.
Every day is a waiting game.
I feel like I'm just waiting out the time until mom is gone.
I fear for the morning when I wake up and she doesn't.
I am dealing with this alone.
I am selfish in that I feel trapped.
I am a horrible person and I am actually very sad every day when I actually do wake up. Most nights I hope I don't make it to another morning.
I have no one to share this with and I had to get it out.
I know no one will see this, but it's eating me up inside and I have to try to get some of it out.