Reporting Losses and Fraud

If you lost your cc or had it stolen, call your credit card company/issuers immediately.
A lot of these companies have 24-hour 800 numbers you can call for emergencies such as this.
Once you've done this, don't worry anymore. According to the law, once you've reported your cards lost or stolen, you cannot be held responsible for charges made after the report.
In any event, your maximum liability under federal law is $50 per card.