A few years ago, my kitty starting sneezing and acting like she too either had a URI or allergies. For over a year I went back and forth to the vet's trying to find out what was wrong with her. A year or so after her symptoms started - she started having this large mass growing on the bridge of her nose. Long story short - it ended up being nasal lymphoma. We had to take her to a teaching hospital 5 hours away for a definitive diagnosis. Unfortuntaely, her cancer had also spread to other organs, so radiation therapy was no longer an option. We ended up doing a 6-month protocol of chemotherapy which successfully put her cancer into remission for two years. If none of the other suggestions work - you may want to consider getting an ultrasound or biopsy to rule out cancer. Good luck with your baby.