Something you can do meanwhile is begin walking after your meals and increase your water intake. Focus on Whole Foods as much as you can. It’s so hard in the beginning. It will be trial and error until you find out what works best for your body.
https://www.gestationaldiabetes.co.uk/ This website is like the GD bible!
They will put in for a glucose monitor and strips to test your sugars at home. You will prick your finger when you get up then an hour after breakfast, lunch and dinner for about two if your numbers are good you won’t have to do insulin. Cut out sugars and cut back on anything that produces natural sugars. Good luck. Hope I helped a bit