I still have brainwebs this morning, so no words of wisdom (yet), just a hug and confirmation that YES, someone here understands. I'm guessing that many of us (me) have been in your situation. Not the exact symptoms, of course, but at the "what's the point" point.
It's draining to have to re-invent ourselves every time something gets subtracted from our lives, and it's especially insulting when there's little left to drain, or so it seems.
Pain - fatigue - anxiety - frustration - any one of those things can be too much, and I'm sorry that you're getting them all at once. Is your doctor being aggressive at helping you deal with what CAN be dealt with? Addressing your pain?
I know a lot of MSers are determined to "fight" this disease and not let it "win". More power to them! If that's what works for you, then I'm right behind you! That's never worked for me. I just get more discouraged when I "fight" and the lesions and the disability don't go away.
The only thing that works for me is to say, "OK, this is the way it is now--how am I going to adapt?" It isn't easy. Usually I go kicking and screaming, shaking my fist and crying. Then I honk my nose, take a deep breath, and try to figure out how adjust the best I can. I'm not always successful. Pain is the worst.
I'm sorry...I wish I had words of wisdom instead of just lots of words!
Someone will be along soon with some useful suggestions. I'm hesitant to say "I know how you feel", but I'm confident saying "I understand."