Hot flashes and other menopausal symptoms, possibly. Shouldn't be a big deal, and it'll ease up as soon as you go back on HRT. I've been off twice, once 3 weeks total for surgery and once for about 4-5 days while my liver was retested. No symptoms at all the latter time, but I was pre-op then. For GRS, I didn't have any significant issues until over a week into the withdrawal. Except that in the first week my, ahem, lower regions resumed normal size and operations. But that won't be a problem for you!