I've cut out sodas and cut way down on sweets. have lost 20 lbs in 2.5 months. is there pathology going on or will dropping sugars lose that much?

Sounds okay to me: Congratulations on losing the weight. I'm assuming that there was weight to lose which would not be pathologic. The amount in that time period sounds like a slow decline and not worrisome. Sugars can contribute to excess calories and definitely add excess weight. If you were underweight to begin with, I would definitely check into your thyroid since you're on medication (right?).

Losing weight : This sounds like intentional weight loss. If so then the weight loss is from the decreased calorie intake. Then no worries.