가상환경에서 패키지 설치 관련 질문입니다.

가상환경 처음 설정하고 pendulum이나 pytest를 설치하는데

자꾸 

(p_study) D:\p_study\Scripts>pip install pendulum

Traceback (most recent call last):

  File "D:\Python\lib\runpy.py", line 193, in _run_module_as_main

    return _run_code(code, main_globals, None,

  File "D:\Python\lib\runpy.py", line 86, in _run_code

    exec(code, run_globals)

  File "D:\p_study\Scripts\pip.exe\__main__.py", line 5, in <module>

ModuleNotFoundError: No module named 'pip'

(p_study) D:\p_study\Scripts>pip list

Traceback (most recent call last):

  File "D:\Python\lib\runpy.py", line 193, in _run_module_as_main

    return _run_code(code, main_globals, None,

  File "D:\Python\lib\runpy.py", line 86, in _run_code

    exec(code, run_globals)

  File "D:\p_study\Scripts\pip.exe\__main__.py", line 5, in <module>

ModuleNotFoundError: No module named 'pip'

같이 에러가 뜹니다. 혹시 어떻게 해결해야 할까요??