Gestational Diabetes diagnosed at 34 weeks

Has anyone else been diagnosed late in their pregnancy? I’ve had sugar in my urine the last few times I was at the doctors. Now I feel guilty and like I’ve done something wrong! What if We caught it too late? I’m plus size but I’ve been diligent this pregnancy and only gained 9lbs so far. I feel like I’ve failed my boy. Anyone else going through this too? What if it has harmed him by not finding out until now? I passed it a few weeks ago when I first did my testing! 🙁