Sorry to hear you are having this issue. I have found to work when I am having an issue with anyone is to document everything. Stop having phone calls with her, and private conversations. I would get everything in email. I do agree knitting is not appropriate during a meeting, but neither is your coworkers behavior.
Now that there is someone new in HR I would request that they mediate a meeting between you and your supervisor. While remembering it’s just business, not personal. I would tell her how her comments affect your work performance, and ask if she has an issues for now on to have her email you about it. It will allow you to both put everything out on a table without concequence of being fired.
I would also watch what you say to your coworkers, though they may have good intensions, if it does get back to your manager. It can possibly cost you your job.
I understand not wanting to tell your employer bout your ADHD, and that you stopped taking medications. However they do need to know that you do have ADHD. If they push about medication, you can politely state that you are not comfortable taking the medication. They can’t fire you over having ADHD.