Are you giving her your expressed milk via bottle or artificial milk? If it's the latter, she may not like it initially as lets face it, its never gunna be a tasty as mummies, lol!
It may be the flow that she is struggling with. BF babies are used to putting effort in to getting milk and when they apply the same effort to bottles, they can feel like they are choking due to their little mouths flooding with milk. Try a newborn/slow flow teats.
Failing that, my 1st and 2nd DD's would not take bottles and the first one used to have to be spoon fed my expressed milk by nursery staff after I had returned to work. Needless to say, she ended up wearing more than she swallowed which was soul-destroying!
Anticipating the same with DD2, I invested in the Haberman Feeder (now called the Special Needs Feeder) made by Medela and sold in Mothercare. It is a pricey bottle - about £17, but worth every penny. It was originally designed for special needs babies like those born with Down's or with cleft paletes, but it was found that breastfed babies also liked them as they have to use the same effort as they would on the breast. The milk has to be worked out, it does not tickle out through gravity, like with a standard bottle.
I hope some of that has been of some use xx