I typed in an artist's name. Instead of hitting the button to play their station, I clicked on something that said in order to hear the specific song on their album, I had to listen/watch the ad. When I did, everything changed. I can't get back to my station shuffle.
It looks like you enabled a complimentary session of Pandora Premium, which allows you to interact with an ad in order to listen to content on-demand.
In the past, free listeners and Plus subscribers were only able to look for artists and tracks in order to create radio stations.
Now, if you search for and select the name of an artist, track, or album, you'll be brought to a "backstage page" where you can either create a radio station OR press play.
If you press play you indicate that you'd like to listen to that content right away (or "on-demand"). Since on-demand listening is a feature for Premium subscribers, you will either see an ad for Premium, or be prompted to watch a video ad to unlock Premium access. Unlocking Premium, will change the app layout to incorporate Premium features, so it may look a little different.
Keep in mind that upgrading to Premium or accepting Premium access is completely optional; you can close the ad and we'll create a station for you to listen to instead (if one is available).
Should you decide to view the video ad and accept Premium access, rest assured that you won't be billed an additional amount for Premium; because the additional cost of these sessions is covered by the advertisement, your account will automatically return to your Plus subscription.