Somebody told me a few years ago (and this isn't a hard and fast rule obvs) that oddly specifically 46 is a real game changer. Oh how I laughed and poo pooed it as I looked relatively young and trim. But blimey they were right. So wierd.I definitely think we age in 'jumps' rather than in a linear way. Obviously there is The Menopause (NB: Sali isn't there yet) but there are other, less obvious, jumps. I think the years that end in 5 are 'jump years' and you suddenly look that bit older.
All to do with menopause I know even if it hasn't manifested itself overtly. Things do even out and get better, but it is like puberty in that your body suddenly seems out of your control for a while. What you did normally to feel good isn't enough any more.
It does get better.