Don't panic, OP! I had diet controlled GD with my DS who is now 16 months, diagnosed at 28 weeks, and this time I developed it right from the beginning, started the metformin by 7 weeks,
First thing is I found NHS diet advice dreadful. It literally would have meant I'd have been on insulin from the get go last time. Try the Gestational Diabetes UK Facebook page for excellent diet advice. Applies to standard Type 2, too. Testing for fasting, post meal levels and the odd spike test for snacks becomes second nature.
You'll be consultant led. In my trust it's initial appointment with consultant, nutritionist and diabetes midwife, followed by consultant visit and growth scan at 28, 32 and 36 weeks.
Diet control advice is induction by 40 + 6, medicated 38 weeks. Large growth might push it to 37 weeks, and a very large baby would be born by elective CS.
My boy was born spontaneously at 38 + 4. I've seen my consultant once this time and she says she will be happy to monitor growth and placental condition past the 38 mark, and treat me as an individual rather than pushing for induction just because. I'll point out I'll be almost 43 by then which does play a role.
It's very manageable with a little planning so try not to worry! Sorry for the epic post it just feels all consuming at the mo.