Is my baby sick?

My 6 month old has had a stuffy/runny nose for the past 3 days and I’ve been using the nose Frieda. But the past 24 hours her nose has gotten worse and every hour I’ve had to function her nose. She has a slight cough but no fever and acts fine and has been eating still. I just don’t know if it’s allergies or a cold or possibly rsv. Her doctors office doesn’t open til tomorrow. Can I give her saline spray and what else could I possibly give her to help her nose?