My DD is just over a week old and I have been B...

My DD is just over a week old and I have been BF and supp feeding as of day 5 due to weight loss. She is feeding for like an hour and a half every feed and it's driving me nuts, she is hungry the whole time!! I have a 2 year old as well and it's damn near impossible to spend that amount of time per feed and then having to settle DD with wind issues on top of that. Am considering just going with formula all the way and see if it makes a difference. Anyone had this same problem? What did you do?