The cough that woke the dead.

I should be resting. I woke up about 15 minutes ago with my chest on fire. It wasn't an asthma attack that I know for a fact but the breathlessness was there. I started coughing non-stop and it went on for quite a while. After about 3-5 mins I started coughing out this yellowish septum... it wasn't thick but it was clear yet yellowish. The coughing continued and degenerated into this dry, hollow cough. The cough was so bad I was practically kneeling on the floor as I coughed out this clear fluid non-stop. The coughing died down after a while but the ache and the whooping sound as I took deep breaths persisted. I decided to google my cough and it seems awfully like a sound clip of a guy having a whooping cough. Unfortunately, my septum isn't offensive smelling and I have never had this before. I vaguely remember stifling a cough about 3 days back but never something as drastic as this. I am getting better now sitting up at my comp, cause lying down isn't too comfortable for me. I hope this is just a one off thing...