1. You can definitely rule it down to sinus issues. What you are describing is a classic case.
2. Have you noticed something - for every new (or old worry), you are able to provide a perfectly sensible answer what is going on. Meaning that you ARE getting better concerning anxiety. You have already gone through phase 1 with flying colors - you learned to find benign explanations for your symptoms, not catastrophic ones. Now it is time for phase 2 - you have to learn to ignore symptoms. I know, I know - some, like aforementioned sinus issues are impossible to ignore, but just like you stopped calling the therapists, you need to stop the self - checking and search for lumps, bumps, itches scratches, freckles and things. They are there and they are harmless -. end of story.
3. Same here - you had a symptom (weight loss) and you have already found a totally sensible and harmless explanation (lifestyle change). Cling to that. Just erase weight loss from your worries. The question was asked - the answer was given. No ifs no buts. Nothing to worry about. The end. Tell this to yourself as much times as you need, but persist with it
Of course, same goes for all other symptoms for which you already have an answer.
4. Imagine how many muscles, nerves and bones are concentrated in our necks. It is one of the most sensitive body parts. So it is normal for it to feel itchy or tender or lumpy from time to time. It is not even a symptom - it is just your nerves, muscles and bones carrying out their normal functions and sometimes, because they have a lot of work to do, they huff and puff. Nothing else
5. Come on, you are Irish and you worry about freckles...Every Irish(wo)man has freckles. You'll be worrying about red hair next
6. Whatever happens and whatever you do, do not doubt for a single minute that you are already better. Of course, anyone can have a rough night or two - but the important thing (it can be seen from your posts, even from your rants) is that you are, generally speaking, back to rational thinking concerning your health. Now anxiety is desperate - it is desperately trying to reclaim the position it previously had in your life by causing you a myriad of strange symptoms. The best policy - ignore ignore ignore
Imagine you are a film star or a politician, you are surrounded by a pack of journalists screaming questions at you and you are just moving through the crowd and saying "no comment". That is exactly what you are doing now with anxiety - whenever new symptom appears, just say no comment