I am heartbroken Kitsu my smallest bun is in the ICU because if a neurological infection

She looked fine i have been grieving the passing of my fiance for the last almost two weeks tomorrow, and i noticed both bunnies were eating a tad bit less but poop was normal. They ran, jumped…
Last night/ this morning very early at 4 am my brother comes to awake me saying “please come I think Kitsune is not ok she is just lying on the floor” i carried her to my bed and she seemed to have trouble staaying up and had pain in the stomach if touched so i ran to the vet i got there 4:30 am they told me she had a neurological infection caused by a digestive onfection that if i noticed her eating anything unusual or lack of eating and i started like torturing myself because yes i nnoticed them both “eating slower” but my stupid mind never though one of them was not eating, two days ago while cooking i had even given Kitsune a smal piece of carrot that she enjoyed happily. I am so lost and so much has been going on that i am like WHY and HOW COULD I NOT NOTICE. Not even my brother she looked really fine before we all went to sleep in the house. The vet told me since it was neurologically advanced she may not survive the following day , days thankfully. I hope she is not in pain it broke my heart seeing her so fragile in the vet and just leaving her there while telling her how much i love her. No visits are allowed. She is 2 and a very small bun, and it kills me. They sent me an update video this morning they told me they would send every day 8 am and 8pm update reports i am ceting and thinkin please not let her suffer she is an innocent soul. Why?
The video i enclosed is the one the vet sent this morning. Sorry if it is too much let me know if i have to mark this post as NSFW or something. She has been having comvulsions i am just broken. So broken loosing my other half to cancer and now one of my babies. Why?