You really shouldn't worry about it at all, considering to track your IP back to you would require the company to go back in their records to find IP's that illegally accessed the site (which is probably hundreds of thousands, if they even have the technology that notices illegal logins), then they would have to pick yours out of all those that were logged, then they would have to contact the ISP that the IP was logged from and ask for the information of the users with "xxx.xxx.xxx.xxx" on that very day (and chances are, your ISP will not divulge the information due to privacy policies most ISP have nowadays).
So, in short, you really have nothing to worry about unless you are just feeling extremely unlucky.
-Chase-