I also know what it feels like to be so panicked.
@vexedgirl .
I've had 2 diabetic cats (one over a decade ago and the other, right now). I've also had a kidney kitty. (He lived to over 18 years of age).
Copper (my kidney kitty) lost tons of weight and muscle through the kidney issue. He also walked on his hocks and wouldn't eat. It *might* be more his kidney issues causing this than the diabetes...but, of course, one works with the other, meaning one makes the other worse etc.. Vicious cycle to be in.
I know nothing of the med you are giving kitty for the seizures but, I'm thinking that it *may* also be a culprit in something???
If this is a kidney cause (saying only *IF*)...then, you're best off to find a low phosphorous food and working with that first (IMO and may be wrong but, this is a diabetes board so, others might have more knowledge and tend to disagree with me on this). There are low phosphorus prescription kibble like k/d that your kitty might eat. Copper was also extremely finicky and though wet food was supposed to be the best for a kidney kitty, he wouldn't look at it either. We did the best we could with the k/d kibble. You might also want to try the g/d and believe it or not, some dog foods are better than the cat kibbles. Seriously.
The other thing that I know worked for Copper was to give him warmed baby food beef/chicken (no onions or garlic added). I know kitty doesn't like wet food but if you can't get the supplement food, you can always mix up a bit of the baby food (also low potassium and low carb) and syringe feed.
And, yes...constipation is an issue that will cause appetite lowering. Our previous diabetic kitty got constipated and wouldn't eat either...therefore, we couldn't give him insulin either. So, that, we had to deal with first and used canned pumpkin (NOT the pie filling but, the canned actual pumpkin). He tended to love it. I know it's not great for diabetes but, in this case...him not eating anything is going to do more damage than the BG issue.
So, I know this is all so overwhelming but, it sounds as though you're trying to fight too many battles all at once and finding road blocks/walls that you're running into that are causing more angst.
Let me just say that *IF* you need to hospitalize kitty to get him/her well....the "fear factor" is not actually a "factor" because it's to save his/her life.
It might be best for you to allow them to put her/him in and do all that they need to do to bring him/her around again and for you to keep your sanity and health as well. You certainly need to keep yours to help kitty and your patients as well as schooling. There's nothing like having professionals do their job and knowing that you're doing all that you can to help this kitty. Fear can be managed in hospital with mild sedatives or something that won't upset the kidney issue.
Maybe, Kitty needs intravenous and med tweaking and let them get him/her back up again? Wouldn't that take some stress and pressure off of you?
Just think about this. If this were one of your patients...telling you the same story of this stress and worry...what would you tell them?
Whatever you'd tell them...is what you need to do for yourself.
Remember, kitty loves what is familiar BUT...when kitty is very ill like this...he/she will love you more for doing what is necessary to get him/her feeling better.
Just hugs!