Noone really quite remembers how hard the newborn stage is several years down the line. otherwise we'd all have just the one 
When you say sleep downstairs with your baby, do you mean on a sofa? You'd be safer cosleeping properly in your bed (kick your DP out if no room), making sure all covers are tucked at waist level, no pillows etc. if you're on a sofa or chair that is much more dangerous from a SIDS point of view. Master the art of lying down feeding and nights will be easy.
You're only ten days in so very early days. The first 6 weeks are the hardest so do everything to make your life easier. The only routine I'd have is get up at the same time every morning, hand baby to DP while you shower and eat, and try and put her down swaddled in the evening while you eat dinner, even if it's 20 mins. If she doesn't settle in the evening (it will happen as she gets older and more alert), eat your dinner and feed feed feed if that is what she wants or try a short bedtime routine (feed, swaddled, soothe to sleep with cuddles) but don't sweat if she doesn't settle. I did this with dd (my second), and she got her nights and days sorted a lot quicker than ds, my first.
In the days, make the most of your baby being tiny and sit down as much as you can. Don't feel pressured into doing house work etc. get a decent sling for when baby doesn't want to nap in the day (it will happen) so you can get stuff done (like eating) while baby sleeps.
Take it a day at a time. Feeding will get easier, you will sleep properly again one day 