Swollen lymph node in submadibular region

Hi there. I am a 24 year old female and for the past few months have had a few strange symptoms. I have had a slightly enlarged swollen lymph node in the submandibular region. This has gotten slighty bigger and has started to occasionally become painful when chewing food. Also for the past few months I have had a strange type of headache. Every night when I lay down to sleep I get a pulling type feeling in the left occipital region that extends up the left side of the head. As soon as I sit up this passes. In addition Ihave suffeered from nausea most days, eye floaters in the right eye and neck and shouder aching. Do you know what could be causing these strange symptoms?

Kind regards,

Sarah