I want to lose weight while TTC

I'm 5'3 and weigh 168. According to the BMI calculator I am overweight. I really want to lose 40 pounds while I try to get pregnant with my second. I get motivated but then the voice in my head says I'll never lose the weight so I get discouraged and tend to give up. I would love to have friends on here who will make sure I'm doing what I need to do and have the encouragement I need to get to where I need and want to be. I work from home so I sit at a desk all day. I'd rather workout at home instead of the gym. So any helpful tips or encouragement is greatly appreciated :)