Sounds like it could be/have been either some kind of bacterial enteritis (gut infection...food poisoning, basically) or some type of protozoan outbreak (coccidia, giardia, etc).. With the fever, my guess would have been enteritis. Antibiotics were/are in order.
Some things to keep in mind, for future reference..
Not having the money to take the dog to the vet doesn't necessarily mean the dog doesn't get its shots...it just means you go to
TSC, buy the shots for $6-$7, and give them at home. It's really not that big a deal. Rabies -- yeah, that requires a vet visit because you can't buy rabies shots, but I'd imagine that lots of low-cost spay/neuter clinics would also be places to get rabies shots for little or no money.
Also, not having the money to visit the vet doesn't necessarily mean you have to do without antibiotics.. You can buy antibiotics -- many different kinds -- OTC at farm supply stores, right off the shelf (or cooler, depending).. Penicillin, oxytetracycline, spectinomycin, tylosin, and sulfamethazine come to mind immediately as I think about the shelf at my local
TSC.. Mail-order houses have all that and more, including sulfadimethoxine (generic Albon), and you can even find OTC amoxicillin and cephalexin that are *supposed* to be used for fish at fish/aquarium supply houses (Fish-Mox/Fish-Flex).. You can also find dog-safe dewormers at most farm-supply stores...fenbendazole for livestock, for instance, is safe (and usually MUCH cheaper) for dogs, provided you get your dosages correct..
Now, don't get me wrong here...I'm not saying "There's no need to ever go to the vet!"... Indeed, my personal thought is that if you have a healthy dog and you know you won't be able to spare enough money to go to the vet should the need arise, it's probably best for all involved to try and rehome the animal with someone who's better positioned to care for it.
BUT...if you find yourself in a pinch where you have a sick animal and an empty bank account at the same time, and something's gotta be done, there *are* things you can do besides wish you had money for the vet.