Please help- throat problem?

I want to apologise at first for being possibly stupid. Nevertheless, id really like proper answers and nobody making fun please ;) I am 21 years old and have been diagnosed with health anxiety. I admit I freak out about anything being wrong with me, but would like to be taken seriously. For around 6 months I have had an on and off cough. Initially I would cough a few times a week, then it went, and lately it has been morning and night, but this has since gone. Whenever I am low or get worried, my sinuses tend to flare up and I get head congestion. Anyway, I have just woken up with the feeling of a lump in my throat. I am in no pain, have no sore throat, no horse voice and as I said, my cough has subsided. What could this be? It is not difficult to swallow but feels slightly 'spongey' when I do. Could this just be phlegm? I am petrified that I have throat cancer, despite the fact that I don't smoke, rarely drink, and have no family history. However, I have had this cough which is a common symptom, but hasn't been 'persistant', or has it? Does persistant mean every day or??? Due to my anxiety I would usually go to a doctor for reurance that I am ok, but I feel silly and don't wish to take an appointment from someone who could urgently need one. I would like to know my chances of having throat cancer at my age, and in fact, any cancer. I am such a worrier that I took to drinking green tea every day as I heard it is amazing for health. Please hlep me, I just want to act my age and not be worried every day that death is just around the corner. Thankyou so much in advance.