VeryGnawty is correct. You can come up with 10 or 1000 reasons for becoming "fat" but the bottom line is there must be an overabundance of input (food) relative to activity to allow a person to build/maintain fat/weight. Estrogen/drugs/menopause can change desires for food and activity but they won't make a person fat without the extra food or lack of activity to build that fat. In other words, estrogen/drugs/menopause can not build fat unless you let those things tell you how much you will eat or how active you will be.
"I have fought excess fat/weight my whole life and since menopause, the 'excess' won't budge at all, no matter what I do or don't do." -MamacatPatch
If the weight won't come off, you have not decreased your diet enough and/or increased your activity level enough. This is simple math and Science that some people do not want to hear. Put every single overweight human being on the planet in a work camp and each end every one of them will lose weight regardless of what condition they have.
You do have control over this. Methinks you already knew this. Don't make things complicated and don't pay anyone money to sell you an excuse that is designed to make you think that your weight is not within your control. You simply have to want the weight off more than you want to eat.