Take conscious note of how that job and its tasks are no longer your responsibility.
How you did what you could or what was required of you already.
How compensation for it did or did not do your work justice.
How the outcome of it without you is not in your hands.
And especially if you are the type to be overly concerned about others, remember that you can only help those willing to accept your help and that you are not obligated to help at the sacrifice of yourself. If it's not doing you well and there's not even enough to make up for it, give yourself permission to walk away without remorse.
There is a form of instant karma that happens when continually offering assistance where such assistance is not properly valued and honored as it would be better offered where it is more deserved (or saved).