When click drawer widget rebuild and value variable change to null

I'm using Riverpod and I don't understand why when I click on the drawer, the widget rebuilds and the variable in my SearchNotifier class becomes null.

Here is my Provider

class SearchNotifier extends StateNotifier<SearchResult> {
  SearchResult? item = SearchResult();

  String? authToken;

  SearchNotifier() : super(SearchResult());

  SearchResult get getSearchResult {
    if (this.item != null)
      return this.item!;
    else
      return SearchResult();
  }

  void setToken(String token) {
    this.authToken = token;
  }

  Future<void> doSearch(SearchObject searchObject) async {
    var logger = Logger();
    //logger.d(searchObject.page);
    final url = Uri.parse(Constants.API_SEARCH);
    try {
      final response = await http.post(
        url,
        body: json.encode(searchObject.toJson()),
        headers: Constants.headerWithAuth(this.authToken!),
      );
      final responseData = json.decode(response.body.toString());
      //logger.d(responseData['foods'][0]['images'][0]);
      if (responseData['response_code'] != "0") {
        throw HttpException(responseData['response_message']);
      }
      SearchResult searchResult = SearchResult.fromJson(responseData);
      if (searchResult.current_page != null && searchResult.current_page! > 1) {
        state.copyWith(
          current_page: searchResult.current_page,
          first_page: searchResult.first_page,
          last_page: searchResult.last_page,
          next_page: searchResult.next_page,
          out_of_range: searchResult.out_of_range,
          prev_page: searchResult.prev_page,
          total_pages: searchResult.total_pages,
        );
        state.foods = [...state.foods!, ...searchResult.foods!];
      } else {
        state = searchResult;
      }
    } catch (error) {
      throw error;
    }
  }
}

final searchProvider =
    StateNotifierProvider<SearchNotifier, SearchResult>((ref) {
  final searchNotifier = SearchNotifier();
  searchNotifier.setToken(ref.watch(authProvider).token!);
  return searchNotifier;
});

here is my a part of Screen code:

class SearchScreen extends ConsumerStatefulWidget {
  const SearchScreen({
    super.key,
    required this.lat,
    required this.lng,
  });

  static const routeName = '/search';

  final String lat;
  final String lng;

  @override
  ConsumerState<SearchScreen> createState() => _SearchScreenState();
}

class _SearchScreenState extends ConsumerState<SearchScreen> {
  var _isInit = true;
  var _isFirstLoading = true;
  var _isLoadMore = false;
  var _isLastPage = false;
  var _currentPage = 0;
  var _nextPage;
  var _listViewController = ScrollController();
  var _gridViewController = ScrollController();
  var _textSearchController = TextEditingController();
  bool viewType_IsListView = true;
  @override
  void didChangeDependencies() {
    if (_isInit) {
      _listViewController = ScrollController()..addListener(loadMore);
      _gridViewController = ScrollController()..addListener(loadMoreGridView);
    }
    _isInit = false;
    super.didChangeDependencies();
  }

  @override
  void initState() {
    // TODO: implement initState
    getData();
    super.initState();
  }

  @override
  void dispose() {
    // TODO: implement dispose
    _listViewController.removeListener(loadMore);
    _gridViewController.removeListener(loadMoreGridView);
    super.dispose();
  }

  void loadMore() {
    if (_isLastPage == false &&
        _nextPage != null &&
        _isLoadMore == false &&
        _listViewController.position.extentAfter < 300) {
      getData(_nextPage);
    }
  }

  void loadMoreGridView() {
    if (_isLastPage == false &&
        _nextPage != null &&
        _isLoadMore == false &&
        _gridViewController.position.extentAfter < 300) {
      getData(_nextPage);
    }
  }

  void getData([int page = 0]) {
    setState(() {
      _isLoadMore = true;
      if (page > 0) {
        _isLoadMore = true;
      }
    });
    DateTime now = DateTime.now();
    String formattedDateTime =
        DateFormat('dd-MM-yyyy HH:mm \'SGT\'').format(now);
    SearchObject searchObject = SearchObject(
      service_type: null,
      booking_date_time: null,
      query: _textSearchController.text,
      page: page,
      filters: null,
      sort_by: null,
      // current do not pass lat lng for test
      // location_latitude: double.tryParse(widget.lat),
      // location_longitude: double.tryParse(widget.lng),
    );
    // new SearchObjectFilters(
    //     price_range: '0-999',
    //     quantity: 0,
    //     meal_type: [],
    //     amenities: [],
    //     cuisines: [],
    //     dietary_needs: [],
    //   )

    // print('search ' + widget.lat);
    // print('search ' + widget.lng);

    ref.read(searchProvider.notifier).doSearch(searchObject).then((_) {
      setState(() {
        _isFirstLoading = false;
        _isLoadMore = false;
      });
    });
  }

  void getEviroment() async {
    await ref.read(environmentVariablesProvider.notifier).getPrefs();
  }

  void changeViewType(bool viewType) {
    setState(() {
      viewType_IsListView = viewType;
    });
  }

  @override
  Widget build(BuildContext context) {
    var searchResults = ref.watch(searchProvider);
    print('Run here!');
    print(searchResults.foods);
    if (searchResults.last_page != null && searchResults.current_page != null) {
      setState(() {
        _isLastPage = searchResults.last_page!;
        _currentPage = searchResults.current_page!;
        _nextPage = searchResults.next_page;
      });
    } else {
      setState(() {
        _isLastPage = false;
        if (searchResults.current_page != null) {
          _currentPage = searchResults.current_page!;
        }
        _nextPage = searchResults.next_page;
        if (_nextPage == null) {
          _isLastPage = true;
        }
      });
    }
    return Scaffold(
      drawer: const MainDrawer(),
      appBar: AppBar(

Here will be null after click drawer. First time load screen I have a data.

Why is it null?