Congrats sa positive test! Yellowish discharge in early pregnancy can happen dahil sa hormonal changes, but since you're still very early at 4+ weeks, better check with your OB just to be sure, especially if it smells weird, itchy, or may pain, kasi sometimes it's just normal pero minsan it could be a sign ng infection na kailangan i-address agad, and you want baby to be safe from the start!