uppity...that's a great question and a really tough question.
Perhaps ask yourself what can you achieve if you stay?
Even if it is only one small thing. Perhaps set a time frame to achieve it.
And consider HOW can you fix what you feel needs attention - do you have the skills and experience?
Ask the people in the area what it is they want fixed - and then consider if you are the person to do it - sometimes we think we know what needs fixing, and that isn't always at the top of others' agenda.
I imagine you are finding it hard to know whether if you choose to leave (even if only to short-term to gain some distance and perspective), whether you will indeed return (life is like that)? Noone knows that.
I wish you well in your decision-making.
I don't think the nagging feeling is guilt... I think it is a sign of maturity and willingness to make a positive difference in people's lives with the knowledge you've gained. That is fantastic.
Sometimes people find a way to achieve great things before they even realise it.
umbrarchist said something about people not responding to his recommendations on books... it's worth reflecting that one book may have had a profound effect on that one person, or perhaps someone they in turn told.... The fact is, the wind scatters these positive 'seeds' and 'we' never know quite where they will end up, if they bear fruit, and who will be nourished by them. But somewhere, someone is.