I don't know about adjusting, but have you gone off your oral meds completely? If you had decent control, I would not have recommended it. By decent control I mean no highs that last more than a few hours and no lows that require someone else's help. I most certainly, as a Type 1, had bgs nowhwere near 100 fasting and 140 post
ever during my pregnancy. Again, that's just me. And why so late? There is no time for adjustment of any kind here.
But having said that, and seeing as you only have a couple of weeks until the baby is born, please talk to your doctor as soon as possible and see if he doesn't feel your bgs were better on orals. Maybe there is some other reason you're on insulin that we don't know about?

what Rikki said on trying to low carb. It's only for a short while. I do feel for you, as this final sprint is the time when you just want to get it over with, especially with a big baby (mine was 4.5kg, and I am 164cm tall).
((Hugs)) Keep us posted!