Infected lymph node in groin?

I have suffered with cysts in my groin for months. I told my doctor as I had began to suffer with them behind my ears and on my face. He gave me a course of antibiotics and said if that doesn't work then there's not much else I can give u. Next to the cyst in my groin a long lump appeared and I thought the cyst had spread into a vein. I left it for about a month but then it became hard inflammed and very swollen. The doc has said I'm on a strong course of abtibiotics which I began on wed. For tge last week u have felt terrible. No energy, tired, a bit queezy and have the feeling that I'm losing my mind amd am not really here...if that makes sense! Three days in the infammation has gone down but the lymph is about an inch long and hard...will antibiotics get rid of.it or do I need to be worried that its cancer? Any advise would be great thank u. :)