Do you eat a lot of carbohydrates like bread as these add to weight gain.
For one, as we women age, it's harder and harder to maintain and lose weight, due to the slowing of our metabolism. I just hit 40, and I notice a difference for sure.
The other symptoms may just be related to you being out of shape, but you really should have a thorough physical done and tell your doc what's been going on. One you get a clean bill of health, you can ask your doc for some diet guidance, and possibly even a referral to a nutritionist.
Good luck!