These little fur balls can certainly keep us on our toes but seriously a 21lb weight loss since April tells me someone is stressing out a lot and probably not eating properly. Guess who? Maybe you wanted to shed a few pounds like so many of us do but that is a substantial weight loss for 3 months!
I know it's concerning when Smiffy won't eat what you think she should eat, when her BG is up, when her BG is down, or she's quieter than usual but if you really think about it, she is one very lucky kitty with a Mummy who makes sure she has everything she needs in life. If Mummy wasn't there, where would that leave Smiffy? We've all had to learn to balance things out and stop worrying quite so much about the stuff we cannot control. Smiffy will eat when Smiffy is hungry. If she eats less earlier on, she will come back and finish off her food later. She will eat more one day and less the next. Right now Looby, Smiffy is doing Ok so try to find a balance to make sure you get food into you too. Losing a few pounds from chasing down Smiffy in the garden or wrestling her out from under a bed may constitute some extra exercise but I doubt that alone has caused your weight loss.
I have a cat with a high dose condition called IAA. For a year I barely saw my cat's BG move at all but now she can suddenly take a dive unexpectedly and that has meant setting alarms for middle of the night tests. Sometimes that has gone on for too many nights and I have to make a decision that Mummy needs a night of uninterrupted sleep or a night out to get my mind off Menace. So occasionally, I give her what is known around here as a big chicken shot so Mummy can have some "me" time. Sure we play a little catch up game afterwards, but I am prepared to deal with whatever she throws at me and that means I am better prepared to keep her safe. I think rule number one of this dance should be that the Caregiver has to take care of themselves first. As they say on an airplane, put your oxygen mask on first, then attend to those who need your assistance.