Creampuff won't eat

It started yesterday, I upped her pain meds to the full dose and she still won't eat, she has not eaten since this time yesterday and since Tuesday has barely eaten at all so I worry about fatty liver disease which sets in very quickly when a cat will not eat and is deadly.
She won't even attempt to drink the liquid diet stuff now.

She had her re-check yesterday and the vet said her mouth was "not as good as they would like" so they gave her a long term antibiotic shot called convenia and I looked it up and it can kill a cat's appetite among other way more serious even[b] deadly things[/b] the vet never disclosed with me, a bad reaction can happen at any time for up to a month, and there is no way to get the medication out of her system if she has a deadly reaction.

I am just so worried and upset, I have this pit in my stomach that makes me feel like I am going to loose her, I keep bursting into tears.



EDIT: she took 2 tiny bites of tuna and drank the water from the can, I offered her more tuna water, 3 kinds of all-meat baby food, the liquid diet, the recovery foo... but shes gone back to acting interested but not eating.

I did not get much into her system but at least it is something, and hopefully enough to stave off the liver issues. She's acting fine, so if her behavior remains normal I will hold off on seeing a vet until tomorrow.

I am still really worried guys, namely because I read about cats suddenly dying from that antibiotic shot up t a week after it was given :/
My vet did not discuss any risks with me at all so I am really peeved, I am a HUGE worry wart to the point of being neurotic so my gut is going to feel like Creampuff could die any moment for a long time because of this.