We can’t fix other peoples issues for them.

We can choose to support them if they are actively trying to fix their own issues.

We can also decide that even though they are trying the impact is too big on us and distance ourselves.

But if they aren’t actually trying to better themselves there is nothing we can do except protect ourselves.

Your sister needs to look into co-dependence and trauma-bonding (if not in this case then for future reference), and focus on becoming emotionally independent rather than confusing nurturing with doormat. She can only fix her own issues, not her friends. And learn that not every friend is worth the title.

Are you sure you’re underperforming, or is that just an idea you came up with yourself? Have you talked to a boss or manager about their expectations for your role and if you are meeting those expectations?

It may just be a self-sabotaging thought, and getting confirmation that you are meeting expectations could let you relax and work at a preferred or natural pace without stressing about your performance.