Am I over reacting over a cold?

My LO is a week shy of 9 months and has so far been overall healthy. I took him to urgent care 4 nights ago for pink eye and nasal drainage. As of today his eyes are looking back to normal and I am still using his eye drops as prescribed BUT he still has a fever and nasal drainage/congestion. I took him to the doctor today and he said it's just a cold and to just use saline as needed. Part of me wants a second opinion but then another part of me feels like I might be over reacting. I just don't like that my son still has a fever. I've been giving him Tylenol about every 4 hours and the fever always comes back. He doesn't have any other symptoms, just the congestion and fever. Is this lingering fever normal or should I take him back to the doctor?