hello everyone

My name is Sandra. I'm a 45yr old mother of 5 grown children an the grandmother of 6. This is my first try ever of dieting. Im 5 ft tall an currently weigh 134lbs. I would love to lose 15 to 20lbs. I work as a night time stocker at a major retail store so my eating habits are all over the place plus The position I have is a very physically demanding one with a lot of walking some nights. The problem I have though is I have tore my rt rotator cuff back in early July an have been put on light duty till after my surgery an healing are complete. I still walk around 8000 to 10000 steps each evening I work. If anyone can give me any help it would be greatly appreciated.. Thanks!!!