Batuk dan sakit tekak ni memang annoying kan, lagi-lagi kalau pregnant atau breastfeeding, a few of us try ginger tea with honey, lozenges yang safe, and lots of fluids, tapi sebaiknya check dengan doctor dulu especially if it's lingering because sometimes kena antibiotics. For GDM, dari what I understand it's really about diet and exercise under doctor's supervision, so definitely kena follow your gynae's meal plan and maybe do gentle walks; I'd suggest asking your doctor to refer you to a dietitian because they boleh tailor untuk your situation specifically.