My 6 months old baby will only feed in the lying down position. If I try sitting up, he will latch on, then pull away, get frustrated and cry, before even initiating my let down. He started this about 2 months ago. We are mixed feeding and I'm pretty sure he has bottle flow preference. Is there a way to feed upright again? I can't feed him when we go out, i have to give him a bottle as I can't lie down when we're out, but I don't like skipping feeds all the time as I worry about my supply so I'm avoiding going out. Any advice please?