Niece doesn’t like kindergarten, what should we do?

About two weeks ago, my niece began throwing tantrums that she doesn’t want to go to school. She has stated many things, like she’s just really bored, her throat and stomach hurt, the teacher is mean to other kids sometimes, it’s cold, I’m scared, and that she wants her mommy to be there. We’ve talked to her teacher and she says that my niece only tells her that she wants her mom. We feel like she is just tired and bored and is looking for any excuse to stay home and watch TV. We don’t know how to get her out of this state of mind. It’s her first year, and we know it is a big change, but she can’t skip school forever. How do we get her to enjoy it and accept it as part of her routine now?