Kathee, I had the same procedure six years ago. I put on some weight, but not that much. Have your habits changed at all? Have you started a course of Synthroid or any other medication yet?
As far as what plan to choose, your thyroid issue shouldn't get in the way of your preferences. (And in any case, a week is NOWHERE NEAR long enough to gauge how good a fit a particular program is.) Like everyone here, you'll have to make a long term commitment to lose weight and keep it off. No tricks - just determination, hard work (maybe some extra), and getting back to plan ASAP when you slip up. For me, calorie counting combined with exercise has worked best.
Having said that, here are some important tips: don't eat or drink anything but water for 20 minutes after a dose of synthroid, don't eat or drink any soy products for 4 hours after a dose, limit soy to one serving a day, and limit cruciferous veggies like broccoli and cauliflower to several servings a week at most. These items have a suppressive effect on thyroid hormone.
Look around the boards here at the different plans, and when you find one that looks good, give it a try and STICK TO IT for a while - like a couple of months at least - before you make a verdict. Good luck!