Make an appointment with an endocrinologist. Maybe it's loss of estrogen or maybe it's hypothyroidism.

I would worry about a strong insulin response from taking in 30 grams of carbohydrates all at once, just so you can exercise.

I would look to hormones as the culprit of your recent weight gain if you didn't change your diet. (Have you entered your foods on FitDay.com to make sure you aren't a victim of carb-creep?)

Best of luck and please keep us posted!