I bf ds at nights until he was about 9m old. He was in a cot in his own room, but would come in with us when he woke, and would then feed hourly? all night. I was exhausted - didn't realise how exhausted until it stopped. The tiredness definitely contributed to my PND.
Then one night I didn't go to him when he cried (hard, but we had already done CC to get him to go to sleep in his cot). He went back to sleep, and literally, that was it. No more night feeds
I still feed him to sleep at 19m (bad mummy I know!), and first thing in the morning. BUT if I am not there, to my great surprise, he is fine. He has a cup of milk, and goes down fine with some wind down time. On occasion he has stayed up and played for hours past his bedtime, but so what? It's only now and again, and if I've had a late night, him having a lie-in is no major problem . Same for mornings. I was on the verge of giving up as I was so tired of having to get up every morning. DH will do one morning at the w/e, but I still did the bf first. Now I don't. DH takes him downstairs kicking and screaming, and within 30 seconds he's fine.
So give it a try - you might be surprised. Enjoy your night out, and don't worry!