Mysterious object on recent ultrasound

Hi all, at 22 I was diagnosed with papillary thyroid cancer that had infiltrated several nearby lymph nodes. After a pretty difficult surgery, NDE, and an equally difficult recovery, I underwent radioactive iodine to clear out residual tissue and have been in the clear for the past decade.

However, recently I’ve really struggled with getting my TSH levels into a good range. All other blood markers are good (including the one that monitors thyroid tissue growth, the name is escaping me right now…)

BUT, when I went in for my yearly ultrasound screening last week, my endo saw something. It was circular, pretty uniform, superficial, dead center of the thyroid bed, and the color-ish of a lymph node (which apparently show up as grey in the ultrasound?)

Of course, I panicked. Is the thyroid cancer back? Was it because of my levels?? Is it something worse? A different kind of cancer? Oh god am I going to die?

The doc said thyroid regrowth was unlikely because I was still taking my medication as prescribed and the other blood markers are good. They mentioned it could even be a rogue parathyroid. They asked if I had been sick recently (I mentioned that I have not been sick, but have had terrible allergies) which would make my lymph nodes irritated.

Well, their reassurance about thyroid regrowth was good but…almost worse ? That means it could be something was worse-like lymphoma? A malignant…something else?

This is all I’ve been able to think about. I’m spiraling. What is the likelihood of another kind of cancer appearing? I just had a basal cell removed last year and I feel like my effing body is falling apart. I’m only 32. I’m a weightlifter and a runner with a great job and a wonderful husband. We’re both health conscious, active, non smokers. I just don’t understand what is happening to me. Any insight is greatly appreciated.