If you were shooting in RAW + JPG, then you do have two files for each exposure. One is the .CR2 file (Canon's RAW format), and the other is the .JPG (processed image jpg). If you are using DPP to view these, you will see two images, but you have an option to show only one image. As for the difference between the two - the RAW format image is usually less sharp and flatter than the JPG, if you have the 'Picture Style" set to one that sharpens and increases the saturation. The RAW image is intended to be processed by processing software like DPP, Lightroom, Camera RAW, etc. The JPG image is intended to be used as a "finished" imaged, whereas the RAW can be considered a digital negative which you can still manipulate extensively.
There are many threads discussing the merits of recording RAW vs. JPG. Do a search with "RAW" and "JPG" as the key words, and be prepared to wade through a lot of discussion, some of it quite heated.