Have you already rebooted the phone after the trouble arose?
What you describe is not normal.
If you didn’t install any new Apps or changed any major settings after the upgrade, then …
… you upgraded.
While there’s nothing much wrong with trying, upgrading an OS installation to a major next version in place may work out … or not, nothing to do with a particular device or OS.
It’s complicated … vendors do the best they can to avoid trouble for their users, but in the end they can only keep their fingers crossed that most of the upgrading will work out fine…
The clean approach, and a way to get rid of trouble possibly introduced by upgrading in place, is to install from scratch … how ever unpopular 
…