My son is 11 weeks old, 6 corrected. He's still waking up every 2 hours during the night for food but when I feed him he's only drinking half his bottle or less, hence him waking up every 2 hours. He is on 120ml bottles but will only eat about 2 full ones in a 24 hour period and the rest of the time he doesn't finish them. Is there anything I can do to help him sleep longer during the night?