Sometimes that happens with duplicate removers, but there's no need to get overly stressed about it. All you need is a file-recovery application that will scan your hard-disk and help you retrieve accidentally deleted files.
Install a tool like Data Recovery Free or Disk Drill, scan the disk partition that contained the deleted pictures, select the images that you want back and the application will help recover them for you.
In case neither of these two free tools can help you, Data Rescue is a highly effective file recovery solution, but it will cost you $99 to get your images back.
Also, try to recover your files as soon as possible. The more new files you copy on the partition, the bigger the risk that your deleted files will get overwritten and become irretrievable.