Hit my iphone really hard on the wall?

I was mad and i repeatly banged my iphone on my door kinda hard then i went to look at it and it still works but it says no sim on it instead of at&t -.- someone help me i already shut it off and it didn't do anything… I know stupid but ughh help

The SIM card is a little card that goes in your iPhone either at the top (iPhone 3) or somewhere else that I'm not sure of for the other generations. You will notice it, it is a rectangle shape and there should be nothing in it or it will be popped out a bit. Look around for a small black plasticy rectangle shape, and then I think a blue, but maybe not, little card that says AT&T on it. Put the card in the rectangle object and then calmly put the thing into your phone. If you did it right it should slide right in, and you are good to go. Please add to you question details with questions if you have any.