My touch screen laptop won't rotate when i flip it upside down or sideways?

It's a lenovo yoga 510. In the past it has just turned normally. And the rotation lock tile has been removed from the action center (the bar that comes up when youswipe from the right.

First the basics to check…
The rotation lock only appears in tablet mode / tent mode and not desktop mode…
I found here, https://support.lenovo.com/...s/ht103981, Check what mode you are in… What Mode are you in?

Have you tried to add the rotation lock back to Action Centre?
Windows key > Settings.
Or
Action Centre > All Settings.
System
Notifications and Actions.
Add or remove quick actions…

.
I would also expect to find appropriate rotation options to your system in graphic properties.unless the display driver has been incorrectly updated…
Go to desktop > Right click > Select "Graphic properties".

There are several other options to look at, but i will wait until you use add details or comment box to report back if you could add the lock tile back to action centre, the mode you are in or use graphic properties?

Type "rotation lock" into the search area.

You have a rotate lock button, unlock it by pressing it. Its a tiddly little thing on the side.