It could be the cause, but there are other causes of epididymitis.
It could be a blockage in the urethra, an enlarged prostate, an e coli infection, an injury, etc.
Have you been on antibiotics recently? If you have, that could skew the test results you took today.
If you have an STD that's causing this, it's one of the curable ones, so at the worst, it's a lesson learned, and you move on, right? Millions and millions and millions of people get an STD each year. If you have one, you won't be alone.
Be careful in the words you chose - you said the anxiety is "destroying you". That's not actually true, right? You aren't being destroyed. There's something called catastrophising. It's a way of thinking that makes things worse for you. https://www.theguardian.com/lifeandstyle/2017/dec/29/stop-catastrophising-expert-guide-psychologist
When do you get your results? Let us know what they say.