Frustrated

I am 23 years old and I have had six pregnancies and only one healthy child, I was recently diagnosed with PCOS and my husband and I have been trying to get pregnant for two years now and we arent having any luck I went to the doctor and he put me on metfomin and told me that it would help my pcos symptoms and help me lose weight well that was three months ago I have lost five pounds and I went back to the doctor today and he told me to lose more weight that it would help. I am a little frustrated thought because I am Five foot no inches and weight 187 lbs. Too much I know but even though I excercise and try to eat right and take my meds it is really hard for me to lose weight and the doc said it was because of the pcos anyway I was wondering if anyone had any ideas that might help me to get to my goal? Anything would be much appreciated Thanks