I think the problem is that Selenium loads up the default browser profile. If you use chrome or a chromium based browser, go to chrome://version
and you should see a heading called Profile Path
copy that and add it to your program with the options method.
Here is a sample:
options = webdriver.ChromeOptions()
options.add_argument("user-data-dir=path_to_chrome_profile") #Path to your chrome profile
driver = webdriver.Chrome(executable_path="path_to_chromedriver", chrome_options=options)
Hope it helps. And yes, make sure you are signed into the account you want selenium to access when you check your path.