Pretty much. Nina said she won't have much of an online presence or even be on the internet at all for a long time afterwards though, so whatever that "stress" is it's messed her up pretty bad.
Reading between the lines and drawing on past incidents there's lack of support from management, social issues, and a lot of negative feedback from fans to consider, but she's not admitting to anything beyond poor mental health and feeling like she isn't living up to her ideals and goals currently at Niji.