This... I'd say this is a clear sign of the society we've become, when more people can relate to this manga than those who don't. 🙁
From personal experience I'd say the hardest part is acceptance.
Accepting the fact that sometimes your best won't be good enough.
Accepting yourself as a person that is flawed.
Accepting the situation you are in, and that often we are directly or inadvertently responsible for it. That it is okay to feel helpless, to feel powerless, but to not let those feelings dictate your future.
Most of all, to verbalize it, to speak out loud, preferably to others, but most of all to yourself. "I'm not okay,".... "but it will be alright."
[Did that make sense?]