Think about it... You left the cats with no supervision for two weeks, but I'm betting you left them enough food and water to last, right? And they aren't sitting in their litter boxes the whole time. Not ideal, but they had what they NEEDED. You just can't set up a frog with food, water, and clean conditions for two weeks.
idk if this would work, but you could try telling a local vet or humane-society worker about your problem. Lots of vet offices have interns and volunteers that might be willing to take the frog for a couple of weeks.
If you post what general part of the country you're in, there might be someone on the forum that could pick him up for a week or two.

I'm trying to give advice without sounding rude. It's just that the two options you gave (leave the frog alone or take it with you) will both almost certainly lead to the frog dying either from poor conditions or stress. Letting someone watch it is the only advice anyone can give.