Articles, a and the

Wednesday, February twenty first, two thousand and seven

Finally, I seem to have caught a cold or the flu, I have a runny nose and a cough now. Talking of "the flu", I don't understand why people usually say "I have the flu." and "I have a cold.", the difference between "the flu" and "a cold". Let me ask my teachers the usage of articles, "a" and "the", next time.
Anyway, let me have a good sleep to get better soon with listening to IRON MAIDEN. I cannot help but listen to the excellent music before I fall asleep well these days. The music makes me feel energetic.