Hello Lesley49.
I feel your pain! I am seven years post meno and the jittery tummy feeling has been a frequent and much detested visitor. Like you I can be completely free of it for days and days and then it comes back for no reason that I can fathom. When it appears I always worry that it will overwhelm me and as you know that just makes it worse. I am also taking an AD and HRT and wondering where to go next!
So sorry that I don't have any solutions for you but if I discover something that works I'll be sure to let you know, in the meantime I hope you find comfort in knowing that you are not the only one struggling with this debilitating meno symptom.
Wishing you well.
K.