Diabetes type 2 when tested for GD

Hi anyone im a little worried. I had a scan and was told baby is on thw big side on 95th percentile. I then got referred to see a consultant which wanted me to do a GTT to test for gestational diabetes. I did the 3 hour test and got a phone call with the results they were really high. The nurse that called me said the results mean i have type 2 diabetes even before i was pregnant but yet i have never been told that never even been diagnosed with that and i was eating everythinv normal sweets choc chips no special diet now im worrying about my baby. Im 28weeks i found all this out 2 days ago what affect will this have on my baby? Does anyone know as i have never been carefull as i was unaware of this. Helllllpppppp anyone