J.S.
I know it's hard, but know that it will get better eventually. You can pull your hair out now trying to figure out a way to get her to sleep better (which she probably won't right now, as it sounds like you've already tried a lot), or you can accept that this is how it will be for a little while and try not to waste the precious energy that you do have trying to figure out a way out of this. My daughter was 10 pounds at birth and other big babies I heard of were sleeping through the night really early on. Mine didn't do it until 10 months old. For whatever reason they're on their own schedule and the best thing we can do as parents, at least for the first year or so, is to switch ourselves over to their schedules.