I'm so sorry to hear of your loss.
Unfortunately, this is why we advocate so strongly to avoid the big box pet stores and buy from a reputable breeder.
It doesn't seem to me that you did anything that could have caused the animals passing.
I certainly don't think this the reason the snake passed, but snakes aren't social animals and aren't the type of pet you take on errands. Please do your new snake a favor and leave your pet at home. There is literally ZERO benefit to taking your snake on errands.
Unfortunately, you'll probably want to forget anything you learned from the big box store employees as well. They're usually minimally trained and clueless on keeping snakes. Of course, there are exceptions to every rule, but this usually the case.
I wish you the best with your new snake.
