I Have Had A Cough For 3 Weeks With Mucus

I have had a cough for 3 weeks with mucus green then yellow. I have sneezing, runny nose, cedar is high where I live, thought it was just allergies, then last two days, dirreahea no stomach ache no pain. Can it be allergies or something worse? I have been taking medication mucenix, motrin, Zyrtec and I never take medication. Could that be what is causing the stomach issue?