Losing your wallet can be a pain in the butt, but losing your credit cards due to theft is an even bigger pain. Not only do you have to go through the process of having the credit cards replaced, but you also have to make sure that you report the loss immediately and make sure that the cards have not been used fraudulently.
The first things that you need to do when you find out that your credit cards are missing - whether due to theft or not - you need to make an accounting of all the missing cards. You then need to call each credit card issuer immediately. In order to be able to do this easily, it is a good idea to be prepared. For each of your credit cards, you might want to keep photocopies of both sides. Make sure that the credit card details are visible as you will need these in case you have to report a loss.
It is important to remember that you have to report the loss of a credit card the moment you discover that it is missing. It is the only way that you can make sure that the credit card will not be used fraudulently. Make sure that you take down the date and time that you make the call for future reference. In addition to this, you ought to take down the name of the person who takes your call. You also need to pay close attention to your next credit card bill and study it thoroughly to ensure that there are no anomalous charges.