Wendy, many of the most knowledgeable and compassionate people on this forum have already made their always-excellent contributions to this thread. Great advice that I hope will help you in this trying time. As someone said above (or if they didn't I'll say it now): take a deep breath. You seem to be in a great place with your team and you're in good physical shape. But most importantly, your attitude strikes me as that of a fighter.
From everything I've experienced and read (mainly on this amazing website, and I encourage you to explore it from the ground up), it does indeed seem most likely that you are
HPV+. And that is a good thing under the circumstances.
Your situation and mine were very similar in that my docs all thought my neck lump was a branchial cleft cyst. I had surgery to remove this alleged cyst and it came back positive for SCC.
But here I am 2 1/2 years later doing quite well and having just had another series of clear scans. And so too will you!
Take everyone's advice about eating a lot (I dropped 30 pounds), getting a TSH test, gathering your friends and family to support you and keeping a positive attitude. You'll also likely be getting fluoride trays after a dental exam.
Every one of us is different. I elected not to get a PEG tube during RT but later regretted it, as I had a helluva time with mouth and throat lesions. But I've always been prone to canker sores so maybe was especially sensitive. Anywho, something to discuss with your team and your family.
Know that we are all here for you at all times. Ask any and all questions, because there's truly no such thing as a bad, stupid or inconsequential one.
And please keep us posted.
Courage!
