Too much amniotic fluid??

Calling all momma's! I had my 20 week ultrasound yesterday. They confirmed we are having a girl. My doctor was out due to the stomach bug, but called today with the report. Everything looks fantastic with baby. All organs were located and looked to be great, saw all chambers of the heart, she weighs 12oz and is measuring 3 days ahead. But I got a call today saying that I have a high level of amniotic fluid and they want me to see an MFM. After years of struggling with infertility and several losses, this momma's heart is breaking. Has anyone experienced this, and it just be a fluke? Doctor didn't seem overly concerned. I AM diabetic, which I know could contribute to the levels. But I also know high levels of amniotic fluid can indicate birth defects. Anyone have any firsthand experience?? Thanks!!