Cant lose weight

I have always been over weight and I gain a consistent amount every year. I have tried everything, visited doctor's, exercise, diet, pills, everything!!! And I cannot lose weight. I have only ever lost weight when I was pregnant and I'm not sure why! When I was pregnant I lost 20 pounds at the beginning and then just maintained that weight the entire time. I had no morning sickness or any change that would have caused weight loss. Now that im no longer pregnant I have gained back all of the weight plus some. I have no idea what is changing or the reasoning. Please help😭