Losing weight

In feb when I started seeing my obgyn he recommended I lose 50lbs before I get pregnant. My weight was 310 lbs. In may I had to have surgery on my cervix cause a biopsy I had preformed came back stage 3 cervical dysplasia when I had my surgery those results came back in june as early stages of invasive cervical cancer. Oct 14th had my 1st check up since surgery weight was at 300 lbs. 2 weeks later oct 28th results r good no dysplasia no cancer my weight is at 294 lbs. I need to lose 34 lbs and I have set a goal to lose 150lbs all together. I have not been having a normal period well no period at all. My dr has put me on metformin to help with my cycle and to help me lose weight. I need suggestions other than walking, drinks lots of water, and the Jillian Michaels workouts I do. What helps you lose weight that doesn't cost money?