I think more likely is that your first pregnancy may have unmasked blood sugar problems (in the same way that first pregnancies can unmask/trigger stuff like chronic hypertension), if there really is an issue, rather than you having gestational diabetes this early. (Similar to not being able to have pre-eclampsia at 6 weeks, if someone has blood pressure problems at 6 weeks, it's most like chronic hypertension.)
I would certainly ask your MFM about doing a 1 hour glucose tolerance test. Since I had GD in my previous test, my MFM ordered one at 6 weeks this pregnancy- but they were testing to make sure I didn't have type 2 since I hadn't been tested in between pregnancies, not gestational diabetes, they'll test for that again later.
Me (29) DH (30)
#1-Olivia Caetlyn-9-28-09-9-28-09, 23+2 wks, emergency classic c-section, class I HELLP, IUGR
#2- Lucas Oliver (rainbow baby)- April 2011, 36+2 wks, HELLP and pre-e free! (lovenox and LDA pregnancy)
#3-Matthew, late October 2012...mostly normal, 37 wks, (lovenox and LDA again)
My blog: http://www.butterflies-and-rainbows.blogspot.com/