No sim card problem on iphone 4s?

I activated my phone through the internet when i got it, so it doesn't have a sim card on it, and its been working just fine for two months. I just dropped it at my house a little while ago, and it says there's no sim card, and i've turned it off and on several times. Is there a way to fix it without taking it to an att store or something of the sort?

Try the Samsung Galaxy S3 if you want a trouble free phone.

Your best option's to take it to AT&T. The SIM card is essentially what keeps the phone activated; when you dropped the phone something to do with its slot (or the card itself) got messed up.