Aih, don't worry lah, at 39 weeks that white milky discharge is super common, even with a slight smell, so your mum friends are right! Tapi since you're worried and also have GDM history, best to just call your doctor's clinic instead of going in blind, sometimes they can check over the phone or tell you exactly when to come, no need for the internal exam straightaway if it's really just normal discharge. A few of us pregnant girls panicked the same way near due date and it was all fine, tapi peace of mind is important kan, especially when you're this close to baby coming. You're almost there!