@Sooverthis1
Yes!
My worst sleeper still managed 2-3 hour stretches when a newborn, but from 6-12m, We'd get maybe 2, 2 hour stints, followed by waking every 15-45m for the rest of the night. And trying to balance that with work and an older child was HARD.
I think its better to be realistic about how it changes, so that you can better prepare for it. So you can sit down together as a couple and work out how to make sure that you get enough rest. If its thought to last a short period, then you're more likely to push through, and end up even more exhausted.
The only reason I didn't go insane with sleep deprivation (even last night I'd only slept 90m by 4am partially because of my toddler) is because of how my husband and I work together to make sure that neither of us is broken tired.
Its interesting that virtually everyone says their first baby is hard, but their second was so much easier. It could be that they are, or it could be that after having a toddler, a baby seems easier in comparison, wheras for your first you've got nothing to compare it to.
None of it is linear. The challenges change so quickly. Their intense physical needs start to decrease, and their emotional needs increase etc.