Have you thought about having your blood chemistry checked? Hormone levels, thyroid levels, vitamin D levels? Perimenopause can last a very long time in some women. I don't have the same symptoms or situation as you, but over the last 10 years (I'm 49), I've experienced more emotional swings than I ever have in the past which I believe are definitely linked to my cycles.
We found that my thyroid levels were a little off (they have since self-corrected after a hospitalization for GYN issues). Plus, my vit D levels were down. It's amazing what a little correction of your body chemistry can do!
Also, I used to get lower back pain all the time with my cycles. Walking regularly helps a lot and I try to do a regimen of tightening my stomach muscles when I walk. Stomach muscle strength helps immensely with lower back issues. The more active you are, the fewer symptoms I used to experience. Are you active enough for your body's needs?