Sounds like your personal info was exposed to a hack as has been commonplace over the past few years (its happened to me as well). If you are concerned about protecting your credit and/or preventing unauthorized credit from being granted, then I would recommend obtaining a credit freeze on all three of the major CB's (Equifax, TransUnion and Experian). The cost is typically 10.00 per freeze and you can pay another 10.00 to lift it temporarily if you need to obtain credit. I believe these can all be placed online with the possible exception of Equifax. This will ensure that no one obtains credit in your name.
Using a freeze blocks potential lenders from reviewing your credit or even seeing a score for that matter. Since they can't see your credit, there is no basis for them to extend you or a potential fraudster any either. I work in this field and this is the best way to prevent identity theft based credit fraud. The CB agencies try to bury it in their websites because it is not as lucrative as their in house monitoring offers.
Along with in house monitoring offers by the CBs, there are other means to try and prevent this type of fraud (putting a fraud alert on your cb, and 3rd party monitoring) however; this is only as good as the lenders ability to see it and recognize it. Most of the time it works but I have seen examples where it is missed and I am sure it costs more than 30.00. If protecting credit is your goal, then use the freeze. Also, sign up for Creditkarma as well and you will be alerted any time there is an inquiry on TU or Equifax. Its free and a no brainer IMO.