I agree with everyone else who has posted - talk to your doctor. And ditch the thermal suit; if you dehydrate you'll be in real trouble, especially in the heat. Drinking plenty of water or other clear, no-caffeine liquids, will convince your body that you have a plentiful supply, and you will lose that water weight without stressing yourself.
Remember, also, that increasing your activity level will increase your muscle mass - and muscle weighs more than fat, but is denser - make sure you are measuring your body in several areas (waist, hips, and thighs are usually good indicators) to see if you are turning fat into muscle. Increasing muscle mass will speed up your metabolism, which will help you lose more weight, and will also aid in your post-surgery recovery, more than just losing weight.
Good luck to you!