At this point, it doesn't matter what caused this, because you have an infection that needs treatment. (Any yellow...orange... green mucous indicates an infection, with varying degrees of seriousness.)

If you are always sick, then you might need to detox your home, and your body. (Allergies could be from food, inhalents or contact.) If you find yourself sicker at night, like for bed, then it's more than likely a food allergy. If you find at certain times of the day...when you are doing a certain task or in a certain place, and your symptoms increase, then it's probably environment. However, I have inhalent allergies also, and some of the cold fronts (depending upon what time of year and from what direction) that descend upon South Florida bring elements I'm allergic to.

I hope you feel better soon.

(PS I take guarana to clear the phlegm and mucous out... it's an herb. I have too many allergies to medications that are synthetic. Go figure. lol)