Hi ollie51

When you say you are on "Evorel 50 sequel" do you mean you are using Evorel 50 (ie oestrogen only patch) all the time and then Provera for two weeks a month, or are you taking Evorel 50 followed by two weeks of Evorel conti AND Provera? (Because Evorel sequi is 2 weeks of Evorel 50 followed by 2 weeks of Evorel conti).
I will assume it's the former? A small proportion of women do not get a bleed at all on sequential HRT and because you are taking Provera for 2 weeks of the month then your lining has not been building up, therefore no bleed especially if you are post-menopause. A bleed under this regime is normally nothing to worry about - however in your case as you have been bleed free despite a sequi regime fo that length of time I would suggest that a sudden heavy bleed should be checked out.
As you say maybe it is the medication you are taking for Addision's that is coming into play - and sorry I can't comment on that but an endocrinologist should be able to advise as well as a menopause specialist. Your doc should hopefully refer you for a scan?
Hurdity x