Well, there could be many reasons. Maybe they're trying to move on and seeing your stories makes it harder. Or perhaps they've found someone new and don't want to give the wrong idea by still being interested in your life through your stories.
It depends. If you still have feelings for them and were hoping for some kind of sign that they still care, then you might be a bit worried. But really, it could be that they're just focusing on their own life now and don't want to be reminded of the relationship through your stories. So don't overthink it too much.
There could be many reasons. Maybe she got busy with something else, like she had to rush to do her homework or attend to some chores. Or perhaps she just lost interest in your story if it didn't catch her attention from the start. Another possibility is that she found something more interesting on her social media feed at that moment.
It's also possible that she's trying to distance herself from you for some reason. Maybe there was something you did or said that made her uncomfortable, and this is her way of creating some space without directly confronting you.
It's possible that he lost interest in the content of your stories. If your stories have been about the same thing over and over, he might have gotten bored. Another reason could be that he has found other sources of entertainment or information that he prefers.
Perhaps there was something in one of your stories that made him/her uncomfortable. It could be a topic, an opinion or even just the way you presented it. So he/she decided to stop watching.
It's possible that he lost interest. Maybe your stories have become a bit monotonous or not as engaging as before. For example, if you always post the same type of content, he might get bored.