I can relate to your problem!! Too tired to bother about friends, visits to friends, or even phoning them!
And for looking after the grandchildren.......I only have a granddaughter aged 5, and I`ve have been watching her on Thursday afternoons since birth. But I find that I watch the clock and count the minutes the whole afternoon. And I go to bed the minute she leaves, I don`t bother about supper or anything, I just want to lie down and die. My husband knows that he has to take care of the rest on that day, I don`t have the energy left, and my pain levels are through the roof.
Keep well, Elizabeth