Email on Phones - Guide
Even though to you your email address and password haven't changed, in the background Microsoft see this as a new e-mail account and as a result you will need to remove the old account from your Mobile and add it again if you want E-mails on your phone.
This can be done by opening the app, tapping on your initials in the top left, tapping the cog in the bottom left and then tapping on Accounts (under General section) and then on your old account tapping this and then scrolling down to 'Remove Account' (I've attached a guide from an American college that may help with this)
Alternatively if you only use this app for work emails then it may be easier to remove the App and then download it again!
As it should have been before you will need to use the Official Microsoft Outlook App from your Phones app store.

Personal Files
Any files that you only need access to should still be stored in your OneDrive, this should now show in This PC as 'OneDrive - James Montgomery Academy Trust - Your Name' if for some reason it has not decided to automatically sign you in then find the OneDrive icon in the bottom right of the computer and Click sign in and enter you Email address, it should then log you in without asking for your password.

Staff Shared - Guide
Staff Shared is now stored on SharePoint, after ensuring your OneDrive has signed in then you can 'Sync' staff Shared for easier access from This PC from visiting this link and Pressing the Sync Button
You will have to bring your Laptop in to school if you haven't already to sort this so that you can then access Staff shared and you should no longer need the Sophos VPN