I'm a 27yr old female. For almost 2 months I've has a swollen lymph node behind my right ear (my dr says might be allergies) when I returned to my doctor 5 days ago he placed me on kefex (antibiotic) for a kindney infection (my 5th this year sense jan 2012) and told me I am hypoglycimic(low blood sugar) now I have a swollen lymph node in front of my ear and the one behind my ear and my breast are sore/tender. What could this be? I'm worried and know that being on antibiotics some tests will not show accurate results so I don't know if going to the hospital could help.