"You need to choose your own level of involvement.
What do you mean by that?
Do you recommend going back to school? Or just getting a shitty part-time job and calling it a day?
Sometimes there is a level of self-entitlement that comes attached with a university degree. There are people that honestly think a job will fall into their lap (I'm not saying that you are). You've already begun by volunteering. If it doesn't work, you'll move onto something else.
As for going back to school, yes. Not just for the credentials, but because you may make a few connections.
Have you ever thought of teaching English abroad? (not as a career, just to pump up your resume)