Dell XPS 9370 - can't log in with PIN, Office 365 broken

This morning I logged on to my laptop and the PIN option doesn't work anymore, had to use password. I have secure boot switched off. Also, my office 365 accounts don't work, but I can log in to them fine in a web browser.

When I try to set up the PIN again, I get this message.

So, I went into the BIOS and switched on Secure Boot. When Windows booted I had to enter my bitlocker key. Booted fine, but I can't set up the PIN.

I then checked the TPM with tpm.msc and it says there's no TPM installed.

I now get these notifications 

and every time I reboot I have to enter in the Bitlocker key. Not sure how to fix. Any ideas?