thanks so much to everyone who has replied 
thigh glad to hear your dad is feeling better.
Cherry we aren't short of stuff to do if you see what I mean - just sometimes I feel horrendous when I'm there.
Whatever I think it was probably a depressing house for a long time, but I was able to just ignore it. As long as two of them could support each other, I didn't have to be there much.
Dint I agree I'm lucky to get my socialising without a huge amount of people, don't get lonely etc. However, I think part of the problem is that helping mum is using up all my "spoons". Not just the emotional ones - the travelling takes a toll on me as well as the general emotional looking after and being around for chat.
Much as I love MN
I do have friends IRL who I don't feel motivated to see, because I'm out of spoons. Even before all this happened, sometimes I'd fix a date with them and wish I hadn't, because life, introversion, A&D use all the spoons just in daily life!
I am in that space where I have to delude myself, I think, or how will I cope? I have to keep telling myself it will be okay.
I do wish I had a crystal ball.
I've got a Buddhist book here and I'm thinking I need some kind of book that has nice Buddhist teachings about the specifics of elderly parents rather than general stuff about compassion. Must be a marketing opportunity there!