Sakit bawah perut tu memang common masa trimester ketiga sebab baby dah besar, ligaments dah stretch, dan gravity aje, tapi since you ada GDM history, better check with your doctor to make sure nothing else going on, especially kalau sakit tu intense atau ada contraction-like feeling. A few of my mum friends swear by pelvic support belt (boleh cari kat pharmacy atau online), it really helps with the lower belly dan back pain without affecting baby. The sleeping part memang susah la, tapi try sleeping on your left side with a pillow between your knees, or propped up a bit, helps with the discomfort. Since your appetite is picking up now, yang penting is quality over quantity, go for protein dan fibre-rich foods which help with GDM control and won't make you feel as heavy. Try to stay active with gentle walks too, it actually helps with the aches. You're doing great managing this while staying positive, that kind of mindset really does make a difference, seriously.