healthy weight

I'm of "normal weight" and 20 weeks pregnant. I'm already up 25 pounds and the avg gain is usually 25-35 pounds the whole pregnancy. How do I I don't want to say diet but how do I not gain any more extra weight. I may have went a little overboard with eating everything and putting in to much weight fast how do I make sure that the weight from here on out is healthy and the baby not just an extra fat layer? First time mom here I wanna be healthy when my baby boy gets here.