Totally get the dentist phobia, I still have it and have to force myself to go and it's a big big deal, for years I didn't go.
It may be that you teeth are very sensitive now that you are brushing, can you try some sensodyne toothpaste? It can take a while, a week or so, to start working effectively but does start to help a bit right away and it does work!
Your progress is amazing, truly, it's leaps and bounds from where you were, I know I keep repeating that but I hope you keep it in the forefront of your mind.
So a year ago you decided you were dying, well, you didn't and a year from now you will probably be looking back going, hmm. Anxiety and depression thrive on those thoughts, create those thoughts, they are dark and menacing and hard to have in your head.
You have decided that medical treatment will be "invasive" and etc etc - you don't know that. Baby steps. It's why I suggested just visiting a walk in clinic. Discuss it with the Doctor. What if maybe you have an ulcer? There are antibiotics that can treat most (google h pylori bacteria). All i'm saying is a chat can't hurt, it will give you something to start. If you never want to go back there, that is your choice. You are free to do as you please, don't forget that.
It can be hard to get effective treatment for mental disorders, you need someone who will really track you and understand what you are going through. Do you have a therapist that perhaps you worked with in the past?