I suspect that menopause is more to blame for the 14lbs than soy milk.
After a "certain age" as the used to say, our metabolisms slow down even more, and it becomes hard to maintain our weight with the old eating habits and even harder to lose weight. So it is good you noticed this in time to modify your food now, before things get out of hand.
Start incorporating a little more exercise and replacing your higher calorie foods with lower calorie dense foods and you'll be right back to the old weight in no time.
And hey, keep us posted. There are a bunch of us in the same situation you are