Welcome
@Jajamcp
My diabetes was originally diagnosed as GD (though it turned out later I'd had it all along but the pregnancy blood glucose picked it up). I remember how frightening it was. Looking back, I think there are two ways of dealing with it: one is to keep eating normally and bank on either being put temporarily on insulin or making it through to the birth without serious effects; or make a change to low-carb eating. The main problem with the first two is that you have to endure several appointments of the nurse insisting that you're not following the healthy plate diet before either the baby arrives or they give up and put you on insulin. The main problem with the latter is that it means making a big adjustment in the way you eat that in all probability you won't need to continue once the baby's born.
I now wish I'd discovered low carb while I was pregnant, but of course that's with the hindsight of now knowing my condition is life-long, not just till the end of the pregnancy, as well as the fact mine was diagnosed at 18 weeks, so I had a lot more pregnancy still to go than you do. On the other hand, if you stuck to it after the birth it would be a great way to lose weight and feel more energetic. For what it's worth, I stuck to the healthy plate diet, put up with being told I must be lying because my levels kept getting higher and fairly soon was put on insulin - and kept on it when a post-natal test showed by blood sugar hadn't come back to normal. I have to say I had no problems with injecting insulin, though I couldn't face injecting it into my pregnant stomach.
Overall, I'd say try not to worry too much: diagnosis this late in pregnancy means you're likely to have GD and nothing else, and if you cut out the really high-carb foods (sugar, sweets and sweet things) you probably couldn't get your BG high enough for long enough to harm your baby even if you tried.
The only caveat is if your readings are really high: are they just a bit above the recommended levels or way up? If it's the latter, I'd suggest you treat yourself as a long-term diabetic and cut down drastically on carbs or insist on insulin.
And finally, I'm not a doctor, and I suspect your doctor/nurse/dietician will give you very different advice. Then all you can do is research as much as you can (lots of good info on this website luckily!) and make up your mind.
Best of luck,
Kate