I don't agree it was mishandled or unrealistic. It was effectively a different work by the time she returned. Aqua and the rest of the cast had banded together to release the behind the scenes footage to clear her name and massively sway public opinion. She felt she had the full support of the rest of the teen actors to have her back during filming sessions (and especially felt a great sense of duty and gratitude for Aqua). Additionally, she learned to compartmentalize her personal self from her acting self, which was the last piece of development she needed to truly become a genius actress with no parallel. Plus, they also did portray the stress she felt toward needing to make a big splash on the show, uphold her contract for her agency/agent, etc.
But even beyond that, she was a young teenager with very little life experience outside of acting on stage. Teenage girls can realistically have big emotions, and no outlet or ability to put things into perspective. The suicide attempt wasn't carefully planned out for weeks, it was a spontaneous and emotional moment of crushing isolation, and that emotional pendulum swings right back in the other direction once she's safe. She felt completely alone with a huge burden to support her family and her agency all by herself, and simply knowing that she isn't alone in all of this could be a direct paradigm shift to change things as instantaneously as she decided to end it all.