Please help me process putting down 19 yr old yesterday

I am still struggling and processing everything that happened. I am afraid I did something wrong. My 19 yr old male cat had hyperthyroidism and arthritis. He was getting Adequan every other week and Solensia monthly. He also was chronically constipated and in order to avoid enemas we were on a SQ fluid regimen every other day about 100 cc. He had previously done miralax and lactulose but that just gave him diarrhea.

So about a week ago he became incontinent in his sleep. He for years has peed in inappropriate places but usually went on pads. About a week ago he peed right where he was sleeping and got himself wet. The next nights I made sure to have pads under him at night, and for a few nights tried diapers. He also had been having increasingly harder time with mobility. He looked like his legs were sore and not cooperating with him. He wouldn’t jump up onto the couch or bed anymore. His back leg would get stuck outside the litter box when he would try to get in. I noticed he had a sore on the bottom of each foot, looked like pressure sores compounded by the fact his feet were frequently wet from urine, even though I tried hard to keep him clean and dry with little waterless shampoo baths.

Yesterday, he could not stand at all. Only lay on a side. I’d try to help him up, or even just sit with both back feet on the ground and he’d flop to a side. He was still eating great, and mentally engaged. I took him to the vet, she’s known him for years, and she said it was time. I asked if I could take him home and have someone come to the house, and she asked if I’d let her put him down there. I agreed because I figured by her asking it was real bad.

She mentioned maybe he was anemic and threw a clot? I am not sure how she knows that. She said his heart sounded good. I am afraid I damaged him by the diapers being maybe too tight around his back legs and hips, or the amount of times he failed to jump up onto furniture when he couldn’t walk hurt him. Or the sores on his foot did it. Did the fluids damage him neurologically? Was he over hydrated? He wasn’t great about drinking fluids and was generally dehydrated that’s why all the constipation. I didn’t think about that until now. I just can’t bear to think I did this to him. 😭Why would he just not be able to walk? It seemed progressive over the week but I am just so heart broken. Any ideas if I did this to him, or was it likely a stroke? Did the Solensia help block some of his pain at least? The night before he died I did give him 25 mg of gabapentin to try to help.

Also- why did the vet hold his head upward when the tech injected the euthanasia? I couldn’t have him look at me, she did let him go, but I can’t handle the idea that he died looking at the ceiling and not at me. Idk if she didn’t want him to see the needle. He never bites and didn’t flinch at all. I’m just afraid he was scared in the last moments looking up at the ceiling. It’s such a blur, she did let go but I am not sure if he was still alive when he looked back at me.

Any experiences or thoughts on this would greatly help. Thank you ❤️