Hi there!

My advise would be stay away from fasting. You may intially lose weight but as soon as you return to normal eating the weight just returns sooo fast!
Fill up on very low calorie foods, like your fruit and vegies, that way you can eat as much as you like and not put on weight. Proteins like turkey, lean meats, low fat cheese, low fat yogurts, no fat milk are filling. cut down on carbs, but stick to wholegrain breads, cereals etc. Snack regularly throughout the day so you never get to the point where your so hungry you'll grab whatever's in front of you.
As for excercise, you do sound very busy! I don't blame you for being tired. just fit any kind of physical acitivity throughout your day if possible & excersise on the weekends.
Hope that helps and good luck with it all!