One of the best bits of advice I was given in the first two weeks was to keep night-time quiet and dark, even when baby is up feeding or whatever... and daytime light and lively. Even when baby is sleeping in cot.
But you're worried about grunts and groans. Okay, babies of your one's age are a succession of weird, scary, is-it-isn't-it breathing noises. It is very unsettling!
As for sleep pattern - I assume you have spoken to the health visitor about this? If you have, and she's seen the baby and is happy, then you don't have anything to worry about.
Seriously, they are pretty tough. Much more than they look! Just get lots of sleep yourself.
I guarantee you, in your future there is a hollow-eyed, grey-haired, exhausted version of yourself, jiggling a screaming baby at 2am, and looking back on these days with yearning.