Ay, that's actually quite normal during pregnancy, lalo na kung first time mo! A few of us pregnant moms experienced the same thing around that time, the hormones are really preparing your body na. But since it's happening kang 5 months pa lang and gusto mo sure kung lahat okay, best talaga na i-check mo with your OB, kasi they can tell you if it's just normal lactation or if may kailangan i-monitor.