Late gestational diabetes

Daisy • 👩🏼👨🏻👶🏼🐶🐶 preggo with first baby boy due 15th July '17 💙
Currently 37 weeks pregnant with first baby boy..
 So I was tested at 28 weeks for Gestational Diabetes by doing the lovely 3 hour Glucose intolerance test. I passed, and was told that I didn't have GD, I carried on with my pregnancy as normal, everyone telling me constantly that 'he looks huge' or that I'm 'about to pop'
So at my 36 week midwife appointment baby was measuring large so they sent me for a scan to see size a bit better.
At 36+5 he was measuring 7'15! The sonograph went on to tell me he would approximately be 9'15 full term. 
2 days later they sent me to a class to learn  how to check my blood sugar levels  at home 4 times a day (before breakfast, after breakfast, after lunch and after dinner) and not to change my diet yet as they need honest results if I have GD or not. 
I'm 2 days into testing and have already had 3 readings that would be considered over the norm (normal being 7.5) I've had readings of 8.4 and 9. 
I'm anxious as it's so late now, and feel like the damage is done?
Why hadn't I failed the GD test at 28 wks or why hadn't they caught this sooner? 
Has any one else been in a similar situation?
Will I get induced early? Will a 10 pound baby pretty much have to be a c section? 
Will my baby be poorly after birth? 
I'm still not aware if I have GD or not but in 2 days out of the 5 having 3 readings over the norm makes me think I do? 
They will ring me in 3 more days to tell me what diet changes I will need to make.. 
which of course I will do any thing for my health and my babies health, but I can't help but think it's far to late already.. 
Any advice would be much appreciated ladies 💙