It is likely that the numbers will go back to normal within a couple of days of the birth,
BUT, and it's a big but... Your numbers were fairly high at 32 weeks. You have a very high risk of developing diabetes within the next 5 years (something you may not even be advised about!), I think it's between 25-50% depending on all your risk factors.
BUT, and again, it's a big but... You don't have to just sit back and wait for that to happen, Change your diet (reduce your carbohydrate intake they way you have during your pregnancy, permanently) and exercise (even a brisk walk 3or 4 times a week) a little more and that could prevent it ever happening.
I had gd in one preg 18 years ago (subsequent pregs were ok as I adapted my diet as soon as I was pregnant, now I'm a bit older, I low carb and check blood sugar every couple of months with my own monitor as a few years ago my fasting blood sugar had started to rise to the highest end of "normal".
It's really low/normal now!
I think it's fairly scandalous that women with GD are not fully informed about the risks of "carrying on as normal"... My sister recently had GD and was given the same rubbish advice I was 18 years ago "carry on as normal, your blood sugar is fine"(with a mention that she might be at a higher risk of diabetes in future).
I suggest you read up (google) info on GD and your future risks, as you are unlikely to get that info from your HCP
.