Using a Picker with CoreData - Saving and fetching data

I am trying to save a string selection from a picker into CoreData, but it is stating "Picker: the selection "" is invalid and does not have an associated tag, this will give undefined results." I can see all the options, but it won't let me click any of them and its throwing that error down below in the console.

I have the following:

'feeling' is defined in my CoreData Entity as a String & defined in my SleepModel type as a String

PickerValues.swift

class PickerValues {
    enum Feeling: String, CaseIterable, Codable {
        case great = "Great"
        case ok = "OK"
        case bad = "Bad"
    }
}

In the AddEntryView.swift:

@State var feelingSelect = String()

Picker ("Feeling", selection: $feelingSelect, content: {
     ForEach(PickerValues.Feeling.allCases, id: \.self){ feeling in
     Text(feeling.rawValue).tag(feeling)
     }
}).foregroundColor(.black)

//inside the function called when clicking the add entry button
var sleepModel =  SleepModel(feeling: feelingSelect)