I'm not sure about the ergo as I' haven't used one, but definitely recommend sleeping with your baby - makes life much easier.
there are a few risk factors - not reccommended if you're very overweight, smokers or on any medications that make it difficult for you to rouse from sleep - amd you should take care to keep baby's face clear of blankets etc.
When very little, I sleep ny baby on my shoulder or arm, or next to me with my arm around them - that gives me reassurance that i won't roll on them and dh won't be able to without first waking me. you might also feel better if dh sleeps elsewhere.
I think it's much safer to do this than risk falling asleep in a chair with baby in arms.
hope you figure out a way to make things easier for you