Coughing up blood every day now & petrified

Hi folks, a few weeks back I woke up one morning and when I cleared my throat what I coughed and spat out was dark blood with clots in it, which as you can imagine freaked me right out, Went to A&E, they did a D-Dimer test to rule out Pulmonary Embolism which was fine. However I  am now finding that every day I am coughing up blood, particularly first thing in the morning, I am not talking about a few specks of blood in the sputum, I am coughing up thick, dark blood with clots. I also now have a sore throat and have a hoarse voice.
 

Now I don't know whether the blood im coughing up is coming from the lungs or from a posterior nose bleed (back of the nose where it meets the throat). The reason I say this is because sometimes (and I'm sorry to be gross) when I can feel like I have a lot of mucus in the back of the nasal passage, I snort it through into my throat and that has also been thick dark blood with clots. So I don't know whether the source is my lungs, throat or my brain or nasal area and that maybe the blood just silently drips down the throat.

Anyway, I am really frightened because I know that what I have is abnormal but i am not being given any answers. I just get told "oh well your CT Scan is clear, your chest X-ray is clear" (actually the chest CT was over 6 months ago now)! I am just not being given any answers and it's really frustrating and concerning as this is not normal!. 

I sometimes want to shout at them to do this test or that test for conditions i have found on Google (I know, I know). this is because instinctively I know that there is something systemically wrong with me but they just haven't found it yet, but equally they aren't doing the tests to find anything either. I just feel convinced that I have cancer but they haven't been able to identify where it is yet. 
 

I would love to hear other's experience in this area.