bullet stops when mouse isnt moving in pygame

Whenever I run this code and I click to shoot a bullet, the bullet moves in the direction it is supposed to go only when I continuously move the mouse. How do I make the bullet move at all times?
I don’t understand why it does this. I appreciate your help! I’m a noobie at this.
This is my code for the game so far:

import pygame
import os
import math

# regular constants?
WIDTH, HEIGHT = 900, 500
window = pygame.display.set_mode((WIDTH, HEIGHT))
FPS = 60
VEL = 5
BULLET_VEL = 8
Sm_L, Sm_H = 50, 50
B_L, B_H = 5, 5
toaster = pygame.image.load(os.path.join("assets", 'indis.png')).convert()
toaster = pygame.transform.scale(toaster, (1000, 500))
pygame.display.set_icon(toaster)
smile = pygame.image.load(os.path.join("assets", "smile.png")).convert_alpha()
smile = pygame.transform.scale(smile, (Sm_L, Sm_H))
bullet_img = pygame.image.load(os.path.join("assets", 'bullet.png')).convert_alpha()
bullet_img = pygame.transform.scale(bullet_img, (Sm_L, Sm_H))


# window draw

def draw_window(toast, smiler, bullets):
    window.fill((255, 255, 255))
    window.blit(toaster, (toast.x, toast.y))
    window.blit(smile, (smiler.x, smiler.y))
    for bullet in bullets:
        window.blit(bullet_img, (bullet.x, bullet.y))
    pygame.display.flip()
    pygame.display.update()


def movement_handler(keys_pressed, smilez):
    if keys_pressed[pygame.K_a]:
        smilez.x -= VEL
    if keys_pressed[pygame.K_d]:
        smilez.x += VEL
    if keys_pressed[pygame.K_w]:
        smilez.y -= VEL
    if keys_pressed[pygame.K_s]:
        smilez.y += VEL


def shoot():
    pass


def main():
    toasterz = pygame.Rect(0, 0, 1000, 500)
    smilez = pygame.Rect(0, 0, Sm_L, Sm_H)
    border = pygame.Rect(0, 0, WIDTH, HEIGHT)
    bullets = []
    mouse_pos = []
    clock = pygame.time.Clock()
    run = True
    while run:
        clock.tick(FPS)
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                run = False

            if event.type == pygame.MOUSEBUTTONDOWN:
                bullet = pygame.Rect(smilez.x, smilez.y, B_L, B_H)
                bullets.append(bullet)
                mouse_pos.append(pygame.mouse.get_pos())
                print(bullets)
                print(mouse_pos)

                pass

            for bullet in bullets:
                mouse_x, mouse_y = mouse_pos[bullets.index(bullet)]
                angle = math.atan2(mouse_y - smilez.y, mouse_x - smilez.x)
                # print("angle in degrees ", int(angle * 180 / math.pi))
                bullet.x += math.cos(angle) * BULLET_VEL
                bullet.y += math.sin(angle) * BULLET_VEL
                # pygame.draw.circle(toaster, (255, 30, 70), (bullet.x, bullet.y), 5)
                if len(bullets) == 2:
                    bullets.pop(0)
                    mouse_pos.pop(0)

            """try:
                pygame.draw.circle(toaster, (255, 30, 70), (bullet.x, bullet.y), 5)
            except:
                pass
"""
        # Basic Control
        movement_handler(pygame.key.get_pressed(), smilez, )
        shoot()
        draw_window(toasterz, smilez, bullets)

    pygame.quit()


if __name__ == "__main__":
    main()