Hi Nikki,
First off, big hugs to you. I've been where you are and I know how hard and overwhelming it is.
She sounds like just a little wee girl, just 10 pounds so let's look at keeping her awake time as short as possible. With newborns, the window of opportunity is so quick, it's better to anticipate the tiredness.
You are doing everything right-- swaddling, setting the stage, doing a wind down routine.
What I recommend is using a soother, when she is way past the point and fatigued. Sucking is soothing for newborns and since they don't have the ability to self sooth just yet, a soother can be a useful tool. Tracy has always recommended using a soother for under 3 months of age.
Now if you are concerned about creating a prop dependency-- make sure she doesn't have the soother in her mouth for the complete duration of her nap. Once she is asleep, and in deep sleep, then remove the soother.
One last thing, growth spurts occur every 3 weeks-- 3 weeks,6 weeks, 9 weeks, 3 months (12 weeks). This will throw off the daily routine and night sleep. When everything goes off kilter and it's around these weeks, then a growth spurt is occuring.
Hope this helps, hang in there it will improve!