When you are on the Calendar screen, does the view keep changing each time you return to this screen?
If you want your Calendar in Week View and it keeps going back to Day View when you return to your calendar screen, this means you have your "cookies" turned-off on your web-browser. Turning "Cookies" on saves your preferred settings each time you visit the same page.
Please note: If you are consistently getting logged out every 15 minutes or so we recommend that you check to see what time limit is set for the Automatic Log Out in your Access Levels. You can go to Settings > Access Levels > Automatically log out after. If you don't have access to see that setting than only the Account owner or someone that has access to change the Access Levels will only be able to change the time limit.
Click on the appropriate link below to learn how to turn-on Cookies in the different web-browsers: