An episode of hemoptysis can be scary! Usually it's a sign of infection, and sometimes it's the body's reaction to a new medication. Chances are you probably just popped a blood vessel when you coughed. It will probably clear up on its own very shortly. Be sure to keep track of approximately how much blood you're coughing up. Also, write down what you were doing when it happened. Keeping good notes about any change in your status comes in handy later.
If you get more than a tablespoonful or two of blood in a short period of time, call your doctor, and get yourself to the ER. They will probably give you a nebulizer treatment with a medication that can stop the bleeding.
As scary as this is, it doesn't mean you've entered a new stage. This sort of thing just happens every now and then. For me it happens when I've been in the cold for too long, or when I switch from TOBI each month. Try not to worry, just keep an eye on it. You'll be okay.