Do I have strep throat?

I have recently been feeling very sick. I have had the common cold for about 3 days, but now my left tonsil hurts when I swallow. One of my friends has had strep recently, so do you think I have it? I am still very sick, so it could still be the cold. Have any of you ever had strep before with these symptoms: I feel tired, frequently coughing up phlegm, sore throat. Thanks !