Like Taz said it won't be a natural period. No-one who is on HRT and remans on it, ever has a natural period as such again, and once you've started HRT, if before menopause then you don't know when you reached menopause. It is extremely unlikely that you haven't reached menopause at 60 - however sheila99 - if you are having natural periods at 58 nearly 59 that is very late indeed! Hopefully you are being checked out just to make sure your late bleeds are not anything serious?
You should still take the progestogen as planned even though you have reduced your oestrogen and had a light bleed as this is a very low dose ie short duration compared to what is licensed as well as long cycle. The bleeding could be due to the lowering of the oestrogen, but you still want to make sure your lining is thinned and shed completely as normal. What dose norethisterone do you take?
Re the sweating and shaking. You would know if it was low blood sugar symptoms as these are unmistakeable - I get them sometimes. What do you eat in the mornings for breakfast and what do you do before 10 am? Also what is your sugar/refined carb intake like? Does eating relieve it? Have you had thyroid checked? What is your weight/BMI like?
Hope you're feeling better today!
Hurdity x