Wow, that's quite small. How tall are you? Do you know how much body fat you have?
Part of this might be you are just naturally small, and as long as you're eating when you're hungry and eating until you're full, it doesn't sound like a *major* issue. Good to hear you feel great.
Have you tried lifting weights to add some muscle? Would probably help you eat more as well.
-Side note, a lot of my family is in Sandpoint...small world.