I apologize you weren't able to get in touch with Support over the weekend! While we no longer offer phone support over the weekend, you can always get support through Chat, Twitter, Facebook or even here in the Community. However I would be more than happy to help you find the Logout button in your account.
You can find this button under the Person icon in the top right hand corner. If you hover your mouse over this icon you will see "Log out" in the drop down of options. Here is a screenshot of this as well:
Hope this helps!
Hello @ClaireC56. It looks like you were able to chat with our Support team shortly after posting here and they were able to assist you. Let us know if you have any further questions!