i had to euthanize my 8 week old puppy after owning him for 13 hours

Got my dog at 7:00 pm. We practiced sit, potty trained on my balcony, and he was in a dog pen area or his crate the whole time. No access to anything except for puppy food and puppy treats.

He was sleeping in his crate, he did so good, he was a natural. At this point he had been fully alert and monitored for every second except when he was sleeping with his snuggle puppy because we put a sheet over his crate. I heard him move at 2 am so I got up to let him out to potty.

He was foaming at the mouth, head lolling back and forth, and then started seizing. We took him to an emergency vet and they couldn’t locate a cause without extensive medical treatment- it was either a liver shunt or epilepsy, but he was so young and a liver shunt would be $10,000 dollars easily to deal with… and confirming epilepsy was extremely expensive too.

Well, under their care he had 6 more seizures in 5 hours. Even after several doses of the sedative, and him being in close to an induced coma, he was still seizing.

At 8:30 am the vet recommended not taking him home to see if his conditions improved, and putting him down instead.

The person who I got the dog from (not a breeder, his dogs just had puppies) had noticed him “zoning out” every now and then. I was worried it was a medical issue but he said he was pretty sure the dog was just really calm. I feel so stupid for not reading in to that more, but I also feel like if I hadn’t adopted him for those few hours, his issue would probably have gone unnoticed for some time… the original owner has a pretty chaotic life and is not a very attentive pet owner.

I just feel so guilty, and now I’m down $860 and just staring at all the puppy stuff i’ve bought. Was there anything I could have done? I had the money for all the regular vet care he could need, but this was just sooo much money, literally on day 1.

I wanted a puppy so bad. I’m heartbroken. RIP, little guy.

Edit: Thank you so much everyone for your kind comments, they have been helping me process everything. I know stories like this are hard to hear, so I really appreciate taking the time to read and respond.