Hi Effie - have popped over from the GD support thread .
Firstly, try not to panic, and try not to google too much!
Most people aren't tested until later unless there are 2 or more risk factors present, or GD in a previous pregnancy. The high blood sugar would certainly be one risk factor. Others can include a previous large baby, being overweight, having a family history of diabetes.
One question worth asking, is can you remember how long before your 12 week bloods you had eaten, and what that meal/snack was, as this may have affected your results. I don't have stats for how common high blood sugar at 12 weeks is, but it isn't something I've come across often. That said, the diabetes midwife that I see told me on my first visit that the early tests are often to try and catch people who had undiagnosed type 2 diabetes pre-pregnancy. She worried me that that was the case for me (I just failed my GTT at 17 weeks), but after monitoring my blood sugars for 4 days, the diabetes consultant was quite definite that it is 'just' GD that I have.
If you fail the GTT (and it is just an if at the moment) then you will need to monitor your blood sugar at home (I do a finger prick test 4 times a day) for a while so that they can ascertain whether the same is true of you.
If you do have GD, then you may need to be induced. This depends largely on whether you can control it through diet or not. So far (am almost 30 weeks now) I have managed to do this, as I also am adamant that I don't want to be induced. If you can't control it through diet/exercise, then you will need to have insulin injections, and should then be induced at 38 weeks. My hospital will let me go to term on diet alone, but will try to induce me if I don't deliver naturally by my due date. I'm crossing that bridge if and when I get to it .
IME it's unusual to be sent home between the blood tests, but I don't think that there are many surgeries who do the tests themselves, so that may be why. It is important not to do much in the way of activity for these 2 hours, so tbh I'd be inclined to take yourself a book into the surgery and sit there and read during the wait.
When are they doing the GTT?