Your GP is wrong. One isn't in menopause until after the last monthly period! Peri can throw up some awful symptoms which HRT should ease though it may be Trial and Error initially. On using HRT 1 cannot know as extra hormones may trigger the ovaries.
Once periods wax and wane we are advised to count for 12 months free of a bleed to consider that we are into menopause, that that is it! However, Nature may throw a spanner in the works so we need to begin from 1.