post-tx, pre-reconstruction breast ultrasound suspicious :(

Hello ladies,

I had stage II, ER+, PR- HER2+++ breast cancer, a total unilateral mastectomy and 6 rounds of chemo plus 25 rounds of radiotherapy which I just finished in late January. All my post-treatment exams came out clear and I was feeling great. But on Friday, I went in for a breast ultrasound, and the radiologist found a slightly thickened lymph node in my left armpit (near the site of the mastectomy). She said, with my history, she couldn't ignore the finding, although the thickening was slight (4mm). So I went in for a core biopsy the very same day.... Now I'm terrified that despite everything, the cancer might have come back.

Has anyone had a breast ultrasound come back suspicious so soon after treatment? Could the lymph node be inflammated by the radiotherapy?

Any advice? I'm so scared.

Hugs,
a 25-yo