Oh poor you, can you not go back to the GP who fitted it? Surely if you have lots of questions and concerns they should address them. I'm absolutely NOT an HRT expert and I think I'd be knocking on their door requesting some reassurance and support.
Some of the ladies on here seem to have a real depth of knowledge re HRT, Dancing girl, Hurdity, perhaps you could ask them? However, if you're not knowledgable yourself how can you have the confidence or experience to start adjusting dosages? Blimey, I'd be completely out of my depth. I've had long old sessions on all sorts of combinations, all with horrible results but everything was managed by specialists. They wouldn't give me a Mirena.
I'm sorry I couldn't be more help to you, I just thought that there may be a connection with this jaw, tooth pain etc and the pesky headaches. I too had a mouth guard made because they wondered whether I was grinding but it became clear I wasn't. I only had the tooth, socket pain etc with the migs.
Get on the phone, start demanding women's rights!