I've followed her here and there over the years, and she's always been up and down with depression and how she perceives herself. To my knowledge she's never explained going through some major traumatic event, so it's more like she gets stuck in her own head over-analyzing everything, and then loses her confidence for a time.
This may get mixed opinions from people, but I've noticed that she posts more content where she's smoking weed or talks about it more frequently in those times where she's not at her best mentally, so it seems like she uses it as a coping mechanism to get her brain to shut up. But I think it's bad for her because she'll then talk about not going to the gym anymore and having less motivation for other things, having gained weight, etc. So it ends up taking her further down a negative feedback loop until something snaps her out of it.
Honestly, out of everyone that I've subscribed to over the years, Erika has seemed like the nicest and most real person, so I hope she finds happiness and stability in her life. It wouldn't be the best for us, but even if that means she no longer posts content online, it could be what's best for her.