Am having total throidoctomy due to cancer and I won't be taking any hormone to replace my thyroid hormone for 6 weeks what side effect I will have?

Hypothyroidism. There is no need to stop the synthroid (thyroxine) prior to surgery. You need to stop it prior to radioactive iodine. You will become hypothyroid: cold, fatigued, constipated, etc. There are ways to lessen this. You can switch to fast acting Cytomel for 4 of 6 weeks, and then stop the cytomel. Thyrogen can be used. The management of thyroid ca is complex, and should be directed by an endocrinologist.
Low energy. People getting prepared for radio iodine treatment need to have a high tsh. Not taking synthroid (thyroxine) is the traditional way to do this. Now there is a medication (thyrogen) which can elevate the tsh, without having the symptoms of hypothyroidism. Usually fatigue, lack of energy are the main symptoms.