I am sorry to hear you are worried about Cujo. My name is***** am a veterinarian and will do my best to help.
I am sorry, too, that you have not gotten help from an expert before now. I just cam online and saw your question.
I am very worried about him, especially since his gums are pale pink; they should be bright "bubble gum" pink. That and his heavy breathing make me worry that he is either anemic (low red blood cells counts) which could be a sign of internal bleeding, infections, or autoimmune disease, or that he has a problem with his heart and lungs.
I am sorry your vet is not available today; is there any veterinarian you could take him to? Waiting until the emergency clinic opens at 6 is not what I would do for my own dog.
Sepsis is possible, but sepsis from a UTI would be unusual. If he is septic, waiting for 12 hours to see a veterinarian is not a good idea; he should be seen immediately.
Cephalexin is a good antibiotic for some kinds of infections (UTI, skin) but not ear infections that can cause his neurologic system to make him walk like he is drunk, being unbalanced, not being