This is something that a Vet needs to see. There are no Vets on this site, & no one can examine your dog online. You need a Vet for this that can do a physical & run tests. There is nothing we can do.
If you are on low income, you may qualify for Animal Humane Association (AHA) low cost Vet clinic. You have to prove your income & if you qualify, your pets can be cared for there. If you receive a government check you qualify.
or you could use CareCredit Vet. They will pay the Vet bill & you pay them back in easy monthly payments. I have used this myself & recommend it when there is no other choice. At least you don't have to come up with a BIG lump sum & you can make payments.
http://www.carecredit.com/vetmed/
It just takes minutes to qualify & your bill will be paid. They will issue you a card you can use any time it is needed but when you first qualify, get the account # & give that number to the Vet clinic. & you will get your card in about two weeks. You are covered from the moment you qualify.