Trac - Glad to see your feeling better.
I didn't know anyone with GD either, but my good friend is Type 1 and my mum is Type 2 9last couple of years) so at least I could talk to them.
I was measuring bigger too (but I am overweight but dr didn't take that into consideration). GD pregancies tend to have lots more fluid too.
Tiredness and lightheadedness could mean low numbers. When you feel like this take your levels and see. If they are low follow your hypo plan.
Yes stress can affect your results, so can illness (usually infections though).
Apparently exercise can help your levels but I found it too hard to walk too far when I was heavily pg so can't comment there.