So I'm back again and this time I seriously think something might be wrong. 
for the last two months I've been having black stuff in my mucus from my nose and throat nearly everyday. I went to the doctors a few weeks back for my anxiety and I told him about it. He said that only smokers have it. He did a thorough check up on me and said that my throat is red. He gave me antibiotics but told me to only take it if I get a fever. 
currently I've got a really bad cough, chest pain and really bad back pain. The black mucus is also not helping. I've got pain near my eyes and cheeks aswell as in my head. I'm not sure if I should take the antibiotics or not. I'm scared this might be some really bad infection that's spread to my brain or some sort of cancer (lung cancer). When I went to the doctors I told him about my anxiety about having cancer and he said the only time you should be concerned is if you're loosing a lot of weight. I seriously don't know what to do. 
I'm sorry that this was a long post but I'm hoping someone will be able to help.