I just killed my budgie
I got two budgies as a gift a year ago, one male one female, and I have a dog and a green cheek conure. I took good care of them, but noticed the male budgie's tail was bobbing and stuff about a week ago, and then he became really weak and basically laid fully flat in his cage last night, and he stopped chirping and barely reacted to touch or anything, only opened his eyes sometimes. I took him to the vet today, and he said he probably hit his head while flying or something so he might have brain damage, then gave me probiotics and vitamin B in a syringe without the needle and told me to feed him from time to time. And I got home a few hours ago, and tried giving him a few drops of the vitamin B from the syringe, and he started choking on it and wheezing and then he just died in my hands. I've been bawling my eyes out for the last few hours and I have no clue what to do. I feel like it's my fault for not administering the vitamin to him properly and I think he might've been curable, but I ruined it. The scene of him wheezing for breath is stuck in my head now and I'm unsure whether I should show his partner his body, or if I should bury him straight away. I feel horrible.