NEED ADVICE PLEASE!!!

I’m 32 weeks and was 163lb and now 216lb. My worry is that so far my Dr. has been telling me I gained way to much weight and that I should eat less and exercise more and my urine samples are always good and my pressure is aswell but other mothers have told me that I should check my liquids cause I’m overweight and I can get diabetes once i give birth or have other complications. Is that true?! Please I need help to know if any mother out there have been on the same page as me as a first time mom and I want to know if it’s too late to start eating nothing but veggies and fruit and maybe a nice piece of chicken on the side and water and salads to try to prevent any difficulties during my labor or after?Or is it to late?