Getting Correct Levels on Zoom H4N

I've been having a problem lately with the Zoom H4N when I'm connecting the output of a wireless lavalier mic to the Zoom's XLR connection at the bottom. The issue is that the recording levels are down to about -30db - I can raise them up in post which works fine but I also notice that I am having trouble really hearing the talent through my headphones attached to the Zoom when recording.

These two issues must be related.

I think I may have accidentally changed some setting on the Zoom recently since I didn't have this bad an issue before.

How do you guys make sure you get better recording levels from the Zoom, I'd like to get a -12db signal recorded (with no clipping of course)