PM Question for those who know

I typed out a PM for someone and hit the send button, but the message went to my "out box" instead of my "sent box" and its still there!?!?
Did the message get sent to the intended person??? I even went back through the edit function and tried to resend it, but all that happened was the date got changed on the message and it is still sitting in my "out box". What am I missing?
Can someone explain this to me?
Thanks!!!

It stays in your outbox until the person opens it and then it goes in the sent box. I like these systems better as you know when the person has actually opened it and read it.
Don`t panic, it has been sent, just not opened.

Oh OK, thanks!