Removing the first element in a linked list C++ - c++

Question

I'm trying to write a function which removes an element in a linked list. I'm only having trouble with removing the head of the list. I'm able to remove any other element just fine. Here's my code (I only included the part of the function which deals with deleting the head).
template <class T>
void SinglyLinkedList<T>::remove(std::size_t i) {
//i is the element to be deleted
SinglyLinkedListNode *p=head;
// checks if the size is 0 or if the node isn't in the list
if( size()==0 && i>=size())
return;
//check if first element
if(i==0){
head=head->next;
//delete p;
}
}
My problem is with freeing the memory (I commented out the deleting here). When I comment it out like I am now it works fine (but obviously results in a memory leak) but when I uncomment it I get a segmentation fault and I'm not sure why. Any help would be appreciated.
Update: I'm sorry, I forgot to include the rest of my code: Here's the implementation:
template <class T>
class SinglyLinkedList {
// Nested class representing the nodes in the list.
class SinglyLinkedListNode {
public:
// The value stored in this node.
T value;
// The next node in the sequence.
SinglyLinkedListNode *next;
SinglyLinkedListNode(T value) :
value(value), next(nullptr) {}
SinglyLinkedListNode(T v, SinglyLinkedListNode *n) :
value(v), next(n) {}
// Return the size (length) of the linked list.
std::size_t size();
};
SinglyLinkedListNode *head;
SinglyLinkedListNode *tail;
public:
// Constructs a new SinglyLinkedList from an initializer_list of type T[].
// This is mostly for convenience, especially when testing.
SinglyLinkedList(std::initializer_list<T> items): head(nullptr), tail(nullptr)
{
if (items.size() == 0) {
return;
}
// initializer_lists were designed to be used iteratively,
// so thats what we do.
auto it = items.begin();
while (it != items.end()) {
this->push_back(*it++);
}
}
T* at(std::size_t i);
void push_back(T value);
void push_front(T value);
std::size_t size();
void remove(std::size_t i);
void insert(std::size_t i, T value);
void append(SinglyLinkedList<T> list);
So I'm creating a linked list using an initializer list and then trying to remove that element. But it's failing
SinglyLinkedList<int> lst = {100, 200, 300, 400, 500};
lst.remove(0);
Update 2: By request here's my push_back function
template <class T>
void SinglyLinkedList<T>::push_back(T value) {
//when empty
if(head==nullptr){
head= new SinglyLinkedListNode(value);
tail=head;
}
//when not empty
else{
tail->next= new SinglyLinkedListNode(value);
tail= tail->next;
}
}