Glucose challenge results and feeling crappy....

[proverbial]

I had a GCT on Sunday and just got a call from the midwife about the results. My level came back as 8.5, so have been booked in for the full tolerance test on Thursday.

I'm wondering if anyone has had this, if thats a high level, how likely is it that I have diabetes, and what happens next?
I have been feeling really crappy for the last while, really really tired, sluggish, bit dizzy on standing etc...but just assumed it was the effect of being 28 weeks pregnant with an under 2 and a 4 year old at home as well!

Any advice?