If I'm not mistaken, an ending is an ending meaning that once you reach an ending the game is over and puts you back to the loading screen. This doesn't really matter with this current version anyway since the endings have been temporarily disabled as they're being reworked.

Best thing I can suggest is to put points into your skill trees like Stardom and Creator. Also, take as many photos of Anna as much as possible.

Hello there,
start at the top, keep the click pressed

It doesn't do it suddenly, you lose subs at the end of a week, and since Celeste appears you start losing subs every week because she takes them away. You need to complete her quest, so it doesn't happen anymore. You can also get the perks on the skill tree to have a chance at not losing subs.