I Have A Hard Rather Large Painful Swollen Lymph Node

I have a hard rather large painful swollen lymph node under my armpit and swelling in my left breast enough to notice that some of my shirts don't fit, I have been on two different antibiotics in the last 6 weeks with no change in the swelling, or pain. Wondering if I am just worrying about nothing everything I know says if it is painful it is not usually cancer, I am a nurse but when it is your body you tend to think the worst, wondering what you think, I have had ultrasound and mammogram, which didn't show much,