VERY swollen lymph node in neck - back to the doc?

Hello,
I am hope for some insight.  i am 30 y female.  about 20 days ago i got a cold sore for the first time.  with it came a very painful spots on my neck, that eventually swelled.  i went to doc, she said, yep cold sore, and swollen lymph nodes, they go together, it will go away.
a week later, the cold sore was gone, and the lymph nodes continued to swell.  i fell worse and worse, tired, a little nausaus, rundown.  i went back to the doc as the lymph node on my left side has swelled to over an inch and i painful, and unsightly!
this time she says the CS and LN are unrelated, so gave me levaquin antibiotics.  three days on the antibiotics, and i still feel rundown, but now my left lymph node is swollen up to 2 inches across.

here are my questions
should i be calling my doctor tomorrow (today is sunday) and getting back into the office?
should i be asking to be tested for anything specific?
shoulld the swelling be going down by now?
any ideas what is acutally causing this? as my doc didnt really give me any info other than "infection?
thanks in advance for any insight.
baeq