DLL w/ Mergesort keeps crashing

I'm trying to figure out why my program keeps crashing fter entering the ID, Name, Email, and GPA. I think it's because of either the void print() function or the void addItem(llist *head) function.

mergedll.h

#ifndef record_H_
#define record_H_
#include <iostream>
#include <string>
using namespace std;

class record;
struct litemLL;

struct llist{
    int size;
    litemLL *first;
    litemLL *last;
};

struct litemLL{
    llist *origin;
    litemLL *next;
    litemLL *prev;
    record *data;
};

class record{
public:

    int id;
    string name;
    string email;
    double gpa;

public:

    record(){ // constructor
        id = 0;
        name = "N/A";
        email = "N/A";
        gpa = 0.0;
    }

    record(const record &copy){ // copy constructor
        id = copy.id;
        name = copy.name;
        email = copy.email;
        gpa = copy.gpa;
    }

    ~record(){} // deconstructor

    record(record&& move){ // move constructor

        id = move.id;
        name = move.name;
        email = move.email;
        gpa = move.gpa;

        move.id = 0;
        move.name = "N/A";
        move.email = "N/A";
        move.gpa = 0.0;

    }

    record& operator=(const record& copyA){ // copy assignment

        if(this == &copyA){

            return *this;
        }

        id = copyA.id;
        name = copyA.name;
        email = copyA.email;
        gpa = copyA.gpa;

        return *this;
    }

    record& operator=(record&& moveA){ // move assignment

        if(this == &moveA){

            return *this;
        }

        id = moveA.id;
        name = moveA.name;
        email = moveA.email;
        gpa = moveA.gpa;

        moveA.id = 0;
        moveA.name = "N/A";
        moveA.email = "N/A";
        moveA.gpa = 0.0;

        return *this;
    }
};

litemLL *split(litemLL *head){

    litemLL *fast = head,*slow = head;
        while (fast->next && fast->next->next)
        {
            fast = fast->next->next;
            slow = slow->next;
        }
        litemLL *temp = slow->next;
        slow->next = NULL;
        return temp;
}

litemLL *merge(litemLL *first, litemLL *second){
    // If first linked list is empty
    if (!first)
        return second;

    // If second linked list is empty
    if (!second)
        return first;

    // Pick the smaller value
    if (first->data < second->data)
    {
        first->next = merge(first->next, second);
        first->next->prev = first;
        first->prev = NULL;
        return first;
    }
    else
    {
        second->next = merge(first, second->next);
        second->next->prev = second;
        second->prev = NULL;
        return second;
    }
}

litemLL *mergeSort(litemLL *head){

    if (!head || !head->next)
            return head;
    litemLL *second = split(head);

    //Recur for left & right halves
    head = mergeSort(head);
    second = mergeSort(second);

    // Merge the two sorted halves
    return merge(head, second);
}

void addItem(llist *head){

    litemLL *temp = new litemLL;
    temp->data = new record();

    cout << "Enter ID: ";
    cin >> temp->data->id;
    cin.ignore(1000, '\n');

    cout << "Enter Name: ";
    getline(cin, temp->data->name);

    cout << "Enter Email: ";
    getline(cin, temp->data->email);

    cout << "Enter GPA: ";
    cin >> temp->data->gpa;

    if(head->last == nullptr)
        head->last = temp;

    temp->next = head->first;

    if((head->first) != NULL)
        head->first->prev = temp;

    head->first = temp;
    temp->prev = NULL;

    head->size++;

    cout << endl;
}

void insert(llist *head, int pos){

    litemLL *temp = new litemLL();

    if(pos >= head->size || pos <= 0){
        cout << "ERROR!" << endl;
        return;
    }

    for(int i = 0; i < pos; ++i){
        temp = temp->next;
    }

    cout << "Enter ID:\t";
    cin >> temp->data->id;
    cin.ignore(1000, '\n');

    cout << "Enter Name:\t";
    getline(cin, temp->data->name);

    cout << "Enter Email:\t";
    getline(cin, temp->data->email);

    cout << "Enter GPA:\t ";
    cin >> temp->data->gpa;
}

void print(llist *head){

    litemLL *temp = head->first;
    temp->data = new record();

    while(temp != nullptr){

        cout << "ID:\t" << temp->data->id;
        cout << "NAME:\t" << temp->data->name;
        cout << "EMAIL:\t" << temp->data->email;
        cout << "GPA:\t" << temp->data->gpa;
        temp = temp->next;
    }
}

void swap(int *A, int *B)
{
    int temp = *A;
    *A = *B;
    *B = temp;
}

#endif

main.cpp

#include <iostream>
#include "mergedll.h"
using namespace std;

int main(){

    llist *head = new llist;

    for(int i = 0; i < 1; i++){
        addItem(head);
    }

    print(head);
    head->first = mergeSort(head->first);

    return 0;
}

//OUTPUT:

//    Enter ID: 12345
//    Enter Name: John
//    Enter Email: jsmith@email.com
//    Enter GPA: 3.5

//CRASHES HERE!!!