I am not sure if I can help you but I have been experiencing similar problems, if that's any consolation.
Before my 2nd child, I was effortlessly, without counting calories or exercising a lot, at a healthy and trim 119 for my 5' 5" frame.
I had a super healthy pregnancy with my 2nd child, but then after that delivery, quite immediately, it seemed, I couldn't lose the weight. I have been between 135 and 140 ever since then, nearly 5 years ago.
I have tried everything I can think of, to no avail. I am finally trying Cron o Meter. It says that I have to consume 863 calories a day if I want to lose 2 pounds a week. 863 means I drink 3 green smoothies of spinach, kale, chard, cucumber & a banana, plus one potato and one rice and bean meal. It is sad beyond sad because my life was so easy before and I never paid attention to amounts.
I also now have cellulite when I didn't before. It's all very sad and contributes to some depression, that I also never had before! Based on this, I think I would be enormous if I ate a SAD diet right now.
My pregnancy (when I was 35) and your possible menopause causing this, hormones might very well be to blame, but what can we do? That is where I've clearly been stuck.
The good news is that menopause won't hit any of us super hard because of McDougalling
I feel semi confident that Cron o Meter, and limiting and counting calories is going to be the only thing that will get my weight off. I am also very thankful for my Vitamix and the green smoothies as they are filling.
Hang in there. I totally understand your frustration so I hope that helps a bit.