In recent times, it seems like my Gmail account has started to sign out by itself, without me doing anything. And not after long sessions of inactivity, could be anything from a few hours to a few minutes. It doesn't happen all the time, but from time to time. Often enough to make me suspect not everything is alright.
Why is that? When I sign in again and check the recent activity, it says that other sessions are in use, and offer me to sign out of them. But among the IPs having been signed in recently, it doesn't show any other than my own.
Could my Gmail account be compromised in any way? How can I find out? What can I do about this?