adj.--- to have too much work/things going on at one time, comes from the feeling of carrying a heavy backpack on ones back
Mike: "Mr. Smith gave us such much homework tonight! I can't believe we have to read eight chapters from Tale of Two cities..."
Josh: "I know, I'm so packed out."
Liz: "Urg, I have way too much going on in my life. Friends, family, homework and my boy friend. It's just too much STRESS."
Sam: "Sounds like SOMEONE'S packed out..."