do we (I) need moral realism?

In my english class, a fellow philosophy student wrote an essay arguing that moral realism requires bizarre, quasi-mystical explanations. He relies on Hume's is-ought distinction: that there is a gap between descriptive and normative statements that we do not know how to cross. Our motivations are simply given (based on impulses we owe to evolution, he argues), and cannot be derived from anything that actually exists in the world. He ends up saying that moral imperatives are groundless as anything but descriptions of how we are compelled to act. There is no way to really grasp an ought.

We aren't supposed to worry though, because society, friendship, trust, altruism, etc. will continue, because we'll have psychological impulses toward them all the same. I can't help but find this viewpoint disenchanting. I'm not sure how our actions can be meaningful, or the choices we make important without some normativity we can believe in.

I don't like pointing to meaning as something important for us, because it seems like such a contentless word. But I feel like our deepest emotions almost force us to aknowledge them as important, that to deny their signficance cuts us off from life. I don't know if moral realism would be necessary to resolve this meaning deficit for me, but the idea that normativity is just our highly developed apish codes depresses me. It also makes me laugh, so I suppose it's a draw.