Honestly the dizziness and so forth sounds more like you are low in iron. Pregnancy often causes anemia, as you are depleting your stores of iron & about 2T is when it kicks in hardest. If you had bad MS earlier, you probably depleted your iron stores extra quickly, and if you aren't eating as much in the way of red meat and getting more calories from those MS-friendly carbs (I'm right there with you on that) that's probably what's happened.
You'll soon get a GD test and you'll find out if your blood sugar is an issue, but I had GD with DD#1 and had no symptoms. I'm also anemic now and taking iron and had some of the same issues you have (and no GD this time) so that's my best advice.