Hice el query para traer los datos de la cita al home page y los desplege en un flatlist.

screens/main/Home_page.js

 import React, {useState, useEffect, useRef} from 'react'
-import { Button, Text, View, StyleSheet} from 'react-native'
+import { Button, Text, View, StyleSheet, SafeAreaView} from 'react-native'
 import {FlatList, ListViewBase } from 'react-native'
 import {TouchableOpacity} from 'react-native-gesture-handler'
 import {List, Divider} from 'react-native-paper'
 import Constants from 'expo-constants';
 import * as Notifications from 'expo-notifications';
 
+
 Notifications.setNotificationHandler({
   handleNotification: async () => ({
     shouldShowAlert: true,
 export function Home_page({navigation}) {
   const [threads, setThreads] = useState([]);  
   const [loading, setLoading] = useState(true);
+  const [appointments, setAppointments] = useState([]); 
   
   const [roomName, setRoomName] = useState('');
 
           name:'',
           ...documentSnapshot.data()
         };
-
       });
 
       setThreads(threads);
+      console.log(threads);
 
       if(loading){
         setLoading(false);
       }
-
     });
 
+    const cita = firebase.firestore().collection('APPOINTMENTS').where('Day', '==', 8).onSnapshot(snapShot => {
+      const appointments = snapShot.docs.map(docSnap => {
+        return{
+          _id:docSnap.id,
+          Day:'',
+          Month:'',
+          Time:'',
+          ...docSnap.data()
+        };
+      });
+      setAppointments(appointments);
+      console.log(appointments);
+    });
+  
+      
     //return () => fire();
     return () => {
       Notifications.removeNotificationSubscription(notificationListener.current);
       Notifications.removeNotificationSubscription(responseListener.current);
       fire();
+      cita();
     }
   }, []);
   
          //});
   }
 
+  
   return (
       <ImageBackground style={styles.stdcontainer} source={require('../../assets/yellow-white.jpg')}>
         <FlatList
           </TouchableOpacity>
         )}
         />
+        <FlatList
+          data={appointments}
+          keyExtractor = {item => item._id}
+          ItemSeparatorComponent={() => <Divider />}
+          renderItem = {({item}) => (
+          <TouchableOpacity
+          onPress={async () => {
+            await sendPushNotification(expoPushToken);
+          }}
+          >
+            <List.Item
+              title={item.Month}
+              titleNumberOfLines={1}
+              titleStyle={styles.listTitle}
+              descriptionStyle={styles.listDescription}
+              descriptionNumberOfLines={1}
+            />
+            <List.Item
+              title={item.Day}
+              titleNumberOfLines={1}
+              titleStyle={styles.listTitle}
+              descriptionStyle={styles.listDescription}
+              descriptionNumberOfLines={1}
+            />
+            <List.Item
+              title={item.Time}
+              titleNumberOfLines={1}
+              titleStyle={styles.listTitle}
+              descriptionStyle={styles.listDescription}
+              descriptionNumberOfLines={1}
+            />
+          </TouchableOpacity>
+        )}
+        />
       <Text>Your expo push token: {expoPushToken}</Text>
       <View style={{ alignItems: 'center', justifyContent: 'center' }}>
         <Text>Title: {notification && notification.request.content.title} </Text>
         title ='Logout'
         onPress= {() => firebase.auth().signOut()}
       />
-      <Button
-        title ='SendMessage'
-        onPress= {() => sendMessage(expoPushToken)}
-      />
         </ImageBackground>
     );
   }
   return token;
 }
 
-
 const mapStateToProps = (store) => ({
   currentUser: store.userState.currentUser
 })