Comando python .\manage.py runserver dexou de funcionar

Boas nao consigo rodar a minha aplicação, erro abaixo:

PS C:\django\connectedin> python .\manage.py runserver
Unhandled exception in thread started by <function check_errors.<locals>.wrapper at 0x03AF0D68>
Traceback (most recent call last):
  File "C:\Users\martins.domingos\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\utils\autoreload.py", line 225, in wrapper
    fn(*args, **kwargs)
  File "C:\Users\martins.domingos\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\core\management\commands\runserver.py", line 112, in inner_run
    autoreload.raise_last_exception()
  File "C:\Users\martins.domingos\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\utils\autoreload.py", line 248, in raise_last_exception
    raise _exception[1]
  File "C:\Users\martins.domingos\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\core\management\__init__.py", line 327, in execute
    autoreload.check_errors(django.setup)()
  File "C:\Users\martins.domingos\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\utils\autoreload.py", line 225, in wrapper
    fn(*args, **kwargs)
  File "C:\Users\martins.domingos\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\__init__.py", line 24, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "C:\Users\martins.domingos\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\apps\registry.py", line 89, in populate
    app_config = AppConfig.create(entry)
  File "C:\Users\martins.domingos\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\apps\config.py", line 90, in create
    module = import_module(entry)
  File "C:\Users\martins.domingos\AppData\Local\Programs\Python\Python36-32\lib\importlib\__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 953, in _find_and_load_unlocked
ModuleNotFoundError: No module named 'perfi'