Flutter Drawer is not working properly in other pages

Question

I have a drawer class in common for 3 pages. Here my problem is if i open any list item page in drawer while in main screen its working fine. if i goto some page(say page2 screen) other than main screen, now if i open any list item in drawer it opens the screen but problem is if i press back button it goes to main screen instead of page2 screen.

Drawer class:

class CustomDrawer extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Theme(
      data: Theme.of(context).copyWith(
        canvasColor: Colors.deepOrangeAccent.withOpacity(0.9), //This will change the drawer background to blue.//other styles
      ),
      child: Drawer(
        child: Column(
          children: <Widget>[
           
            Padding(

              padding: const EdgeInsets.only(left:8.0),
              child: ListView(
                shrinkWrap: true,
                children: <Widget>[
                  ListTile(
                    leading: Icon(Icons.event_note,color: Colors.white),
                    title: Text("Menu",style: TextStyle(color:Colors.white),),
                    onTap: () {
                    Navigator.push (
                          context, MaterialPageRoute(builder(BuildContextcontext)=> Menu()));
                    
                  
                    },
                  ),
                  ListTile(
                    leading: Icon(Icons.person,color: Colors.white),
                    title: Text("My Profile",style: TextStyle(color:Colors.white),),
                    onTap: () {
                      Navigator.push (
                          context, MaterialPageRoute(builder: (BuildContext context) => MyProfile()));

                    },
                  ),
                ],
              ),
            )
          ],
        ),
      ),
    );
  }
}