DarkxAngel20, I frequently leave FB on when I'm not at my desk and return an hour later to find messages which I didn't know arrived. And then when I do return, it's often to turn off the computer because I'll be doing other things and so the messages never get replied to. It's not that I'm deliberately ignoring them, it's just that my world doesn't revolve around responding to messages.
If you want to spend quality time with her, ask her on a date.
Edited to add: if she's just come home after three days at camp, she's probably too tired to respond.
Never regret anything that has happened in your life. It cannot be changed, forgotten or undone. So, take it as a lesson learned and move on.