Basically thought I had fluid on my knee 5 weeks ago doctor seems concerned rushed me for aloud of test

blood 

x ray 

mri results shown mass in my knee and the back of my leg witch only then I found the mole that caused it all anyway since that they took biopsy of both tissues n Last Friday I just had results to say it's melanoma but it's spread n it's a tumour in my knee I'm having surgery on Monday absolutely *** myself 

but thus week i went down to visit a friend ended up her ringing ambulance on me coz all my lymph noid in neck n face swelled really bad hospital did more bloods confirmed its infection in lymph noids seriously is it possible guna be to with the cancer or is their other infection u can have in them, I'm 33 and single mother n all this to find out n try take in is just mind blowing if someone could get no with any advice or information I'd be grateful