I know you're probably scared at this point, but your kitty's health is in dire need of attention. I fully second what @StephenQ has suggested. Your little guy needs some kind of IV nutrition, something to stop the diarrhea, and more fecal testing than what's done locally in-house. Don't give up fighting for your baby. Get him to the new vet, or I know Houston is big enough to have several emergency vets. Get him to one TODAY. I know it's late in the day, but find someone to see your baby today. Keep us posted and know we're pulling for you and your kitty.