Doubly-Circular Linked list. New node not inserting. C++

Question

So this new node is supposed to be inserted after the last node. I can't figure out why that is not happening. Note: The list has multiple elements before this function is called (approx 5) so as of now it only has to work for that case. The last node should point to the top node and the top->prev pointer should point to the last node. Where have I gone wrong? I'm assuming that its wrong by the way because the last node never prints when the print function is called

void CircularDLL::insertAfterLast (int id, string name, string email, int age)
{
 Node* N=new Node;

 N->stId=id;
 N->stName=name;
 N->stEmail=email;
 N->stAge=age;

 Node* Q=top;

 while(Q->next!=top)//get to the last node
 {
  Q=Q->next;
 }
 cout<<"Q next is top now"<<endl;
 Q->next=N;
 N->prev=Q;
 N->next=top;
 top->prev=N;

}