Do I really have to feed her?

I feel really bad about this, but I hate feeding Isabella! In fact, no one likes feeding her. In the hospital, the lactation nurse said that she has a "high palette" and she holds her tongue up in the roof of her mouth. It's very difficult to feed her because she wants to keep her tongue up there- so the milk pools under her tongue... then next thing I know, she's spitting it all out. She can't drink it if it's under her tongue. I have been told to try different nipples since she has a hard time sucking. But after 4 or 5 different nipples, I don't know what else to try! Also, since she has trouble sucking, it takes her 30-40 minutes to drink a bottle.... but Jonathan finishes in about 10 or 15 minutes. Am I a horrible mommy?? Surely not!!!
Any suggestions would be greatly welcome!