I was just wondering on something. Why does my mom only act like she has bipolar with me and no one else?

When we meet new people, we do want to give our best impressions so we show a certain side of ourselves that's not to say that your mom might be putting on an act, we just try to show our best selves to the world. With you, I'm guessing that because you're close to her/have lots of contact with her, that it will be hard to keep up appearances for long periods of time. Whereas for everyone else, they may not spend as much time with her as you do. It's always those that are the closest to us that we hurt the most. If you do feel stressed out about it, please reach out to someone for help- perhaps another family member or one of the listeners here :)