J.L.
Aww, sorry to hear about your little guy. Nobody likes a sick child! I'd ask the doctor to take a listen to his chest and possibly take an xray. Pneumonia can sneak on quickly and the low grade fever indicates some sort of infection somewhere. An xray can give you a good idea if it's just congestion or something worse. As terrible as it is, it may just be a bad cold that needs to run it's course. Since these days can blur together, keep a little log of what is happening with him. It'll help if/when the doctor is asking questions. Best of luck in being a strong mommy!!