Gaining weight too fast

I had lost 90lbs right before I got pregnant, I was on vyvanse for adhd and binge eating. When I found out I was pregnant I stopped taking it and have been gaining weight way too fast. I’m now 30 weeks and my doctor is now getting concerned with the weight gain. It’s making me super stressed so I thought I’d replace a lot of what I was eating for healthier options. I also mostly only drink water. I rarely drink anything else. I try to go on small walks through the day. I don’t have gestational diabetes. I thought making healthier choices since my last appointment would slow down the weight gain and it hasn’t. Does anyone have any suggestions? I’m really stressed about it