Use to work in the USA

So this summer I was working in the USA, and on my way back I forgot to hand in the VISA back to the immigration officer, but in my work package it said that I could send it to an American immigration address so i did that as soon as i got home.. I know it was received but am still kind of freaking out that they won't let me cross the border to visit for 5 days. Im sure its fine, but is there anyway to tell? I never had had any trouble crossing the border before.

you will have no problems. even if you hadn't sent it, your showing up at the border now would show that you had left US and it has not been that long after your I-94 lapsed.