Am i sick or allergies?

So i went to bed with a little stuffy nose. Like the stuffy nose happened only when i laid down to go to sleep. I woke up twice during the night and needed to swallow the mucos in my throat. Woke up with mucos in my throat and all day feels like my throat is itchy and i have flem in it, like i keep clearing my throat and mucos comes out. Other then that nothing else. No headache nose is fine and no sore throat. I live in the chicagoland area but have not been outside too much lately. Do you think I am getting sick or is this allergies. Might/ I add i took a zrtec at midnight. Could that of caused it since I took it when I went to sleep?