What is wrong with my daughter?

I have a 21 month old daughter. She has had a cough and congestion/runny nose for over 2 months. She has taken 2 antibiotics (Amoxil and Omnicef). She coughs worse when running around or when very upset. She has never wheezed as best we can tell. Her lungs sound clear each time we go to the doctor but the cough is awful. The cough is worse at night as well. She was started on Zyrtec every day at the beginning of everything and then changed to Allegra 1/2 tsp BID about 3 weeks ago. Nothing is helping. She has no history of asthma or other respiratory issues and no history of such in our families. She does have eczema and allergies to milk, eggs and peanuts. I am at a lose. The doctor mentioned we may have to start treating it as asthma even though there is no wheezing and try Flovent but I hate to start that diagnoses. The docotot says her throat has looked really red the whole time and 2 weeks ago when we went her tonsils were red and swollen. Do you have any ideas about what it could be?