You're lucky, as by the end of my wife's 2 pregnancies she has basically had 24-hour/day heartburn and been completely miserable, such that sleep was difficult.
The good news is that you will eventually get used to getting by on much less sleep. The part that sucks, as I'm sure you've been told, is that it is going to be a loooong time before you're able to sleep in again. Small kids don't give a fuck that it's the weekend, and they don't give a fuck how late you stayed up the night before. They wake up early EVERY SINGLE DAY. That is tough. But, in like 15 years they'll want to sleep until noon everyday and it will piss you off, so you have that to look forward to, or so I'm told.