Weight loss with a sedentary job

Hi I'm 28, at 5'7 and about 158 lbs. Would like to get to 148-150 lbs but I have a very sedentary job with (somewhat) long work hours. Most of my extra weight is around my mid-section. I'm scared I won't be able to lose it at all after a pregnancy. Used to be fairly athletic (badminton) before starting my career 3 years ago. Any advice on how to work myself into a routine where I can squeeze in exercise during the week? Slow but steady weight loss is fine. Will be TTC by July this year. Thanks!!