Whats wrong when you have fliud draining from your noise to your throat and you cough out blood

There is nothing seriously wrong with drainage going down your throat.  If you cough out the drainage and it is blood-tinged, you probably have some inflammation going on in your sinus cavities.  The bleeding occurs because the areas of the nasal membranes contain many capillaries and they are close to the surface of the tissue. Anything from trauma (getting hit in the nose) to inflammation will cause the tissue to bleed.  You can relieve this by getting a humidifier for your bedroom or other rooms you frequent.  You can also try a neti pot that will flush your sinuses and offer some relief as well.