Well, we ended up in the ER, but we're home now with some answers.
As I was getting Carter ready for his appointment today, he started to turn a very pale gray color and his lips were very blue. Typically that would mean that his Oxygen levels were low, but according to his monitor he was at 100%.
Then he started crying, and he wouldn't stop which is VERY unlike Carter. We decided that it would be best to take him to the children's hospital, so we started out on the one hour journey. About half-way there, Carter was freaking out so badly that I took him out of his car seat and held him the rest of the way. Anyone who knows me, knows that I'm a freak about car seats, so that should tell you how bad it was. When we got there, he finally fell asleep.
We were fortunate enough to get a Resident Doctor who had done a rotation with the Infectious Diseases team while Carter was in the NICU. He remembered Carter before he'd even come into our room. I don't typically pay much attention to Residents, but this one was on top of it. On our way to the hospital, Michael and I had discussed different things that we thought it might be, and we thought he may have an Urinary Tract Infection. Carter takes a low dose of Septra (an antibiotic) to prevent those since his urine refluxes back into his Kidneys. When he was sick last week, the doctor put him on Amoxicillian and told me to hold off on the Septra until the Amox. was done. Evidentally the Amox. wasn't strong enough to fight off UTI's because that is exactly what he had. After a respiratory viral panel and chest X-Ray we got the positive on the urine cultures. We're really lucky that we got this particular doctor because he agreed with our theory and tested his urine while the Attending thought it was probably a waste of time and was pushing for something respiratory.
All is good. We're home now, and he's sleeping peacefully.