It's Thursday, so if your hedgehog hasn't eaten since Sunday, you are in an emergency situation. A visit to the vet is not optional.
You absolutely must call your vet, let them know what's going on, and have them see her as soon as possible.
In the meantime, you need to get some food into her. Don't worry as much about nutritional value as you do appeal. High fat, wet cat food is a good place to start. Chances are, Blue Buffalo makes a wet version of your current kibble, but you don't necessarily have to start with that. You also need to syringe water if they're not drinking (though wet cat food will help with dehydration, as well).
To be very honest, since it's been 4-5 days, your hedgehog is most likely extremely ill, and you may want to prepare yourself for a lack of recovery. But the most important things are getting food into them and getting to the vet.