Mak, itu kemungkinan besar mucus plug yang keluar, tanda tubuh kamu memang sedang prepare untuk labour, tapi doesn't mean you're going into active labour dalam few hours lagi. One of my mum friends pun keluar brown mucus 1-2 minggu sebelum dia deliver, jadi timing dia berbeza-beza untuk setiap orang. Since you're already 38 weeks and due soon, I'd say just observe lang, if you get regular contractions, water breaks, or heavy bleeding, that's time to call your doctor or go to hospital. Tapi for now, keep calm and stay close to your maternity notes, best to ring your midwife or OB tomorrow just to confirm everything looks good, especially since this is your first time. You're so close now, mama!