My experience:
Hourly waking for either feed, wind, change nappy (and everything else if poonami inc YOUR clothes/hair needs washing - seriously it gets EVERYWHERE), cleaning up after vomit/spit up, colic/reflux, lonely and wants a cuddle...
While dd was colicky she couldn't sleep laying down only on our chests so we took it in turns.
2 loads of laundry per day
Usual housework still needs done, plus you still need to eat and drink especially if breastfeeding.
You'll be recovering from the birth too, even more tiring if it was traumatic for any reason, you have wounds healing - I'd had emcs so very sore and tired.
Well meaning visitors.
Midwife/hv visits - first vaccinations are at 8 weeks. Ah yes! Needing to pack half the house to go out anywhere!
Tiny babies can still get colds, coughs. My dd also had hayfever.
Baby's dad needs to accept hobbies are on back burner until further notice - you'll BOTH be parents!
Who told you they sleep 14-18 hours?
Bf - nipples get used to it, can be sore at first but gradually gets less so and then one day it's not sore at all. Personally I preferred bf it was relatively easy (once dd and I learned), no faffing with bottles, free and much easier for going out and about. But ff has its pros too. I had to ff from 9 months as my milk dried due to medical condition. I found it a faff washing, sterilising and making up bottles, dd hated waiting either for it to cool down or warm up and it took us several attempts to find a brand she wasn't intolerant too, I also needed to use latex teats as she couldn't manage silicone ones, also had to use specially shaped bottles as she got a lot of wind. But it did mean her dad and others could do feeds sometimes which meant I could get a lie in or early night. If baby has a sensitive tummy which meant bf mum had to be careful what she ate/drank then ff obviously negates that issue.
Every baby and every parent is different. You won't really know until baby here. Though having said that I've been looking after babies since I was 14 and my last time doing so was just 3 years ago, so almost 30 years experience and I've yet to meet a newborn that sleeps for more than 4 hours in the daytime and even that's rare. Most under 3 months (ime) wake roughly every 2-3 hours. Mainly due to small tummies needing regular top ups or emptying!