Basic calc do-while main menu loop error

// Basic calculator MISSING MAIN MENU LOOP
#include <iostream>
#include <conio.h>


using namespace std;



int main()
{
    //Main Menu Loop Attempt

    do
    {

    int choice;

    //Main Menu
    cout << "Enter the number next to the calculation you would like to use, or \n if you would like to exit." << endl;
    cout << endl;
    cout << endl;
    cout << "1. Addition" << endl;
    cout << "2. Subtraction" << endl;
    cout << "3. Multiplication" << endl;
    cout << "4. Division" << endl;
    cout << "5. Exit" << endl;
    cout << endl;
    cout << endl;
    cin >> choice;



    //Addition statement
            if (choice == 1)
    {
        double firstNumber;
        double secondNumber;
        double result;
        char returnToMainMenu;


            cout << "You chose addition." << endl;
            cout << endl;
            cout << "Enter the first number: ";
            cin >> firstNumber;
            cout << endl;
            cout << "Now, enter the second number to add: ";
            cin >> secondNumber;
            cout << endl;

            result = firstNumber + secondNumber;

            cout << firstNumber << " + " << secondNumber << " = " << result << endl;
            cout << endl;
            cout << endl;
            cout << "Would you like to return to the main menu? (y,n):";
            cin >> returnToMainMenu;
            //cout << "Press any key to exit.";

            //getch();
            return 0;
    }

            //Subtraction statement
    else if (choice == 2)
    {
        double firstNumber;
        double secondNumber;
        double result;
        char returnToMainMenu;

        cout << "You chose subtraction." << endl;
        cout << endl;
        cout << "Enter the first number: ";
        cin >> firstNumber;
        cout << endl;
        cout << "Enter the second number to subtract: ";
        cin >> secondNumber;
        cout << endl;

        result = firstNumber - secondNumber;

        cout << firstNumber << " - " << secondNumber << " = " << result << endl;
        cout << endl;
        cout << endl;
        cout << "Would you like to return to the main menu? (y,n):";
        cin >> returnToMainMenu;
        //cout << "Press any key to exit.";
        //cin.get();
        return 0;
    }
            //Multiplication statement
    else if (choice == 3)
    {

        double firstNumber;
        double secondNumber;
        double result;
        char returnToMainMenu;

        cout << "You chose multiplication." << endl;
        cout << endl;
        cout << "Enter the first number: ";
        cin >> firstNumber;
        cout << endl;
        cout << "Enter the second number to multiply: ";
        cin >> secondNumber;
        cout << endl;

        result = firstNumber * secondNumber;

        cout << firstNumber << " * " << secondNumber << " = " << result << endl;
        cout << endl;
        cout << endl;
        cout << "Would you like to return to the main menu?(y,n):";
        cin >> returnToMainMenu;
        //cout << "Press any key to exit.";
        //cin.get();
        return 0;
    }
    //Division statement
    else if (choice == 4)
    {
        double firstNumber;
        double secondNumber;
        double result;
        char returnToMainMenu;

        cout << "You chose division." << endl;
        cout << endl;
        cout << "Enter the first number: ";
        cin >> firstNumber;
        cout << endl;
        cout << "Enter the second number to divide: ";
        cin >> secondNumber;
        cout << endl;

        result = firstNumber / secondNumber;

        cout << firstNumber << " / " << secondNumber << " = " << result << endl;
        cout << endl;
        cout << endl;
        cout << "Would you like to return to the main menu?(y,n):";
        cin >> returnToMainMenu;
        //cout << "Press any key to exit.";
        //cin.get();
        return 0;
    }
    //Exit statement
    else if (choice == 5)
    {
        return 0;
    }
    //Invalid choice loop
        do
    {

        cout << "You entered an invalid choice." << endl;
        cout << "Please choose one of the following:" << endl;
        cout << endl;
        cout << endl;
        cout << "1. Addition" << endl;
        cout << "2. Subtraction" << endl;
        cout << "3. Multiplication" << endl;
        cout << "4. Division" << endl;
        cout << "5. Exit" << endl;
        cout << endl;
        cin >> choice;
    }
    while (choice < 1 || choice > 5);
    }
    while (returnToMainMenu == 'y');

    return 0;
}