You can check your Premium subscription status by accessing your Eight menu (via the ‘gear’ icon in the top right of your profile) and tapping on ‘Premium settings’. If you instead see options for subscribing, it means you are not subscribed currently.
You can also check your current subscription status via your App Store or Google Play account:
App Store: [View, change, or cancel your subscriptions]
Google Play: [Cancel or change a subscription on Google Play]