Hi there,
It's such an awful feeling having a high when pregnant, so I feel your stress. (I'm type 1, on a pump, have the Libre and am 37 +4 days pregnant with baby no.2). With me, I have been resistant to insulin for most of this pregnancy so it seems to take an age, plus much more of a correction to get my levels down from a high, which adds to the stress. I've been type 1 since I was 17 and I'm 39 now, and I don't know about you, but I cope pretty well with my condition in the main, but pregnancy and diabetes is so hard to control as it's ever changing and so unpredictable.
My hbalc is currently 48, 6.5% ish which my midwife is pleased with, but I too have had lots of short-lived highs of 14-18, for no apparent reason, which I'd preferred didn't happen. If it makes you feel any better, my hba1c was about 6.8 percent with my son five years ago and he was, and still is, fit and well. He was born via planned section at 38.5 weeks, no need for special care, 9lbs and healthy. With a week to go until section number two, (eek!), I'm hoping and praying this time it's a similar story as the worry of highs is quite a burden. At my last scan about 2 weeks ago, the baby was already measuring at 42 weeks and 7lbs ish, so I can't help but thinking is that my fault, or would I have big babies without diabetes anyway. My son is in size 7/8 clothes and over 4ft already at just 5, so who knows.
I know I'm not out of the woods yet, but I wanted you to know I get completely where you're coming from, have one success story, and have heard similar to other replies that as long as you correct straight away, it's not cause for major concern.
My midwife who's a diabetic specialist too had someone in training the other week and she said when you have a patient like me, who's trying their very best, she thinks healthcare professionals should try harder to recognise how hard it is to manage diabetes in pregnancy and no matter how hard you plan or try, sometimes you get unexplained results that are no fault of the patient. I thought this was nice to hear as sometimes I've felt so guilty and responsible when I've had highs.
Anyway, good luck, sounds like you're doing well. I'll not say don't stress, as I know you will, but just check regularly and correct, and speak to your team if you need help. Even this last week I've had to increase my basal rates on my pump to counteract overnight highs as the baby is growing still. It's so ever-changing.
Take care and all the best.