This isn't the year to try to accomplish everything. It's okay - and even necessary - to pursue what matters most to you, and to say no to some things that seem like you should do them. Will what you're pursuing give you a sense of community...

...contribute to people or to a solution that matters to you, preserve your wellness, or open up other opportunities?

"Matters to you" is different from "scares you." Naturally, I think that leadership development programs like http://wilsonleader.ca  and http://mccallmacbainscholars.org  are great. So, if they scare you AND matter to you, apply.

And if you'd apply only because it would be a line on your CV, keep looking for stuff that matters to you, captures your curiosity, or instantly feels like at least an 8/10.

Feel like you don't even know what you want? That's normal, too, and @MacSSC's excellent career counsellors can help with that.