If you feel bad about formula, get a good breast pump and pump milk to put in a bottle for baby, and let other people feed her sometimes too. I actually nursed AND used formula.

I co-slept with my son, so night time feedings were easy. My warning about this would be you have to know that you are the type of person who won't roll over on baby. I knew I wouldn't because I had already spent years with one or more cats always snuggled up next to me and was used to always being aware of where little bodies were in relation to myself while sleeping. If you aren't sure of this, there ARE little baby co sleeping safety beds you can put in the bed with you, or you could use a moses basket in bed with you. There are other types of beds for baby that can be right up next to your bed that would make it easier to quickly feed baby and go back to sleep.

It will be easier to sleep at night as baby starts eating more foods too. As babies grow bigger and can have foods that are more filling, they sleep longer.

Really, I was exhausted pretty much until my boy was about 4-5, but by about 9 months, the sever sleep deprivation had passed.