I am making a 2D game and ran into a problem where if I try to setup parameters for my isRunning to make my character run, it seems to stop the crouch from changing the speed of my character but lets my crouch input disable my collider still. If I disable or take out the code for my isRunning so that he cannot run, my crouch speed works just fine and vice versa. Most likely a problem with my code as I am very new but any tips or solutions is greatly appreciated 
lines to look at would be around 71-139
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Player : MonoBehaviour
{
//The speed our player will move
[SerializeField] private float _speed = 3f;
[SerializeField] private float _jumpSpeed = 15f;
[SerializeField] private float _airborneSpeed = 0.25f;
[SerializeField] private float _runSpeed = 5f;
[SerializeField] private float _defaultSpeed = 3f;
[Header("Ground Check Values")]
[SerializeField] private float _groundCheckDistance = 0.15f;
[SerializeField] private float _verticalOffsetModifier = -1.75f;
[SerializeField] private float _horizontalOffset = 0.1f;
[SerializeField] private LayerMask _layerMask;
private void Awake()
{
}
//the attatced Rigidbody2D on our gameobject
private Rigidbody2D _rigidbody2D;
private SpriteRenderer _spriteRenderer;
public Animator _animator;
[SerializeField] Collider2D standingcollider;
//Read input from our keyboard on the X, Y Axis
private float _input;
private bool _isJumping;
public bool _isGrounded;
private bool _isFlipped;
private bool isRunning;
private bool crouch;
public Transform attackPointTransform;
private void Start()
{
GameObject attackpoint = AttackPoint.attackpoint;
_rigidbody2D = GetComponent<Rigidbody2D>();
_spriteRenderer = GetComponentInChildren<SpriteRenderer>();
_animator = GetComponentInChildren<Animator>();
}
private void Update()
{
HandleInput();
_animator.SetFloat("Speed", Mathf.Abs(_input));
_animator.SetBool("Jump", _isGrounded);
// store movement from horizontal axis of controller
Vector2 move = Vector2.zero;
move.x = Input.GetAxis("Horizontal");
if(_input > 0)
{
_isFlipped = false;
}
else if(_input < 0)
{
_isFlipped = true;
}
_spriteRenderer.flipX = _isFlipped;
if (Input.GetKeyDown(KeyCode.S) && _isGrounded)
{
crouch = true;
}
else if (Input.GetKeyUp(KeyCode.S))
{
crouch = false;
}
if (Input.GetKeyDown(KeyCode.LeftShift) && _isGrounded)
{
isRunning = true;
}else if (Input.GetKeyUp(KeyCode.LeftShift ))
{
isRunning = false;
}
}
// determine direction of character
private void FixedUpdate()
{
_isGrounded = Checkgrounded(_horizontalOffset) || Checkgrounded(-_horizontalOffset);
HandlePhysics();
_isJumping = false;
}
private void HandleInput()
{
_input = Input.GetAxis("Horizontal");
//An "if" checks the brackets beside it and, if true, executes the code within its scope
if (Input.GetButtonDown("Jump") && _isGrounded)
{
//As long as you make a new variable as a part of an equation, you can auto generate it with CTRL + Period
_isJumping = true;
}
if(_isGrounded && crouch)
{
standingcollider.enabled = false;
}else
{
standingcollider.enabled = true;
}
if (crouch)
{
_speed = 1.5f;
}
else
{
_speed = _defaultSpeed;
}
if (isRunning)
{
_speed = _runSpeed;
}
else
{
_speed = _defaultSpeed;
}
}
/// <summary>
/// Sets the player xVelocity based on _input,
/// and sets the player yVelocity based on _isJumping
/// </summary>
private void HandlePhysics()
{
float speed = _isGrounded ? _speed : _speed * _airborneSpeed;
// if(_isGrounded = false)
// {
// _speed = _airborneSpeed;
// }
// else
// {
// _speed = 8f;
//}
//Add force adds force each time it's called to the referenced rigidbody
//_rigidbody2D.AddForce(new Vector2(_input * _speed, 0f));
float xVelocity = _input * speed;
//A ?' used as part of an equation, acts as an if/else statement
// where if the equation/bool to the left of the ? is true
//the value is set to what's written in the left of the ':', else it'll
//use whats written to the right of the ':'
float yVelocity = _isJumping ? _jumpSpeed : _rigidbody2D.velocity.y;
//if (_isJumping == true)
//{
// yVelocity = _jumpSpeed;
//}
////An else is executed only when the above "if" is false
//else
//{
// yVelocity = _rigidbody2D.velocity.y;
//}
//A Vector2 is a type that contains 2 floats. A x value and a y value
Vector2 newVelocity = new Vector2(xVelocity, yVelocity);
//Velocity directly refertences the current velocity of the rigidbody
// using = you can directly change the current velocity of the rigidbody
_rigidbody2D.velocity = newVelocity;
if (_isFlipped == true)
{
//attackPointTransform.transform.position = new Vector3(transform.position.x * -1, transform.position.y, transform.position.z);
// AttackPoint.Getcomponent<AttackPoint>().Positionconstraint = enabled;
attackPointTransform.transform.eulerAngles = new Vector3(0, 180, 0);
}
if (_isFlipped != true)
{
attackPointTransform.transform.eulerAngles = new Vector3(0, 0, 0);
}
}
private bool Checkgrounded(float groundCheckOffset)
{
Vector2 offset = new Vector2(groundCheckOffset, _groundCheckDistance * _verticalOffsetModifier);
Vector2 origin = offset + (Vector2)transform.position;
if(Physics2D.Raycast(origin, Vector2.down, _groundCheckDistance, _layerMask))
{
Debug.DrawRay(origin, Vector2.down * _groundCheckDistance, Color.green);
return true;
}
else
{
Debug.DrawRay(origin, Vector2.down * _groundCheckDistance, Color.red);
return false;
}
}
}