About 2 weeks ago, my 3 month old kitten started sneezing... alot. Now he even sounds congested when he first wakes up. Then about 3 - 4 days ago I started noticing a drop of blood on his anus after he "used the litter box". I've looked at his stools and I've never seen anything more than a spec of blood but the stools are pretty loose (not liquid) and last night and today he's been pretty lethargic (not at all normal). Also, his inner eyelids show about 1/2 the time now. Could this be due to me changing his food too fast (from Nutro to Felidae) or does it sound more serious? Please Help!!