What if you break your iPhone sim card?

I have an iphone 4 and recently bought a 5. I wanted to switch my iphone 4 sim to my iphone 5 (to get all my data). However it didn't fit. So I tried cutting it (I read online you could do that) Well It snapped and doesn't work. So now I'm out a sim card. What do I do? Did I loose all my data (I backed it up to iTunes earlier in the day). Should I go to att and get a new one. If I do will I get my data back? Also I did not buy the phone from att I got it on craigslist if that matters.

You will need to get a new Micro Sim Card.

You will not lose anything. Just make sure to do a complete backup of your iPhone4 and then do a complete restore with your iPhone5. You sim card is useless with iPhone luckily. Lol Nothing on it really.

The 4 uses microSIMs whereas the 5 uses nanoSIMs (smaller than microSIMs). Oh there wouldn't have been data in there anyway aside from contacts (if you had them stored there), & maybe 1 or 2 texts.

All the data you are worried about is on the iPhone itself.

Just go to your carrier & ask for a new SIM with your number on it. That's all.