Hi and Welcome ho-totty
When I had to have my bloods done fro FSH etc. I had to come off HRT fro a month otherwise the tests wouldn't have been correct. I was 40 when I had these tests done and had been on HRT for over 3years, - I even had, what I thought was a period during this break from HRT but the blood tests still showed a very high FSH and low oestrogen. I was then put on Oestrogel and progesterone pills as sequi. I never knew when my periods actually stopped but I think it was around age 43 as I found I needed more oestrogen after that. I came of HRt at 49 for another break and absolutely on periods emerged and my oestrogen level plummeted.
If you want to go onto conti HRT I'd come off HRT completely for a month and have tests done then. Why do you want to go onto conti HRT? Some women prefer to stay with sequi as one can get more side effects with conti HRT. DG x