Although your question is a bit unclear, it sounds like you may have shot the photos with the camera set to B&W? To do this with a Canon camera one selects the Monochrome picture style. Or maybe you shot the images with another picture style setting that rendered color images on the camera's preview screen but now when you open them in a raw editing application on your computer they are being rendered in B&W?
Either way there are a couple of things you should keep in mind about the difference between the main information stored in the raw file and the jpeg preview image produced by the camera and displayed on the camera's LCD at the time you take the photos:
- Regardless of what photo style and other in-camera development settings are chosen when you take the picture, all of the data collected by the sensor is saved to the raw file. The development settings (white balance, contrast, saturation, etc.) are saved on the side as a list of ways to interpret the raw data, but all of the data collected by the sensor is still contained in the actual raw data.
- The picture you see on the back of your camera is not the raw data. It is a preview image that is a jpeg developed by the camera from the raw data using the in-camera development settings at the time the image was taken. This jpeg preview image is also attached to the .cr2 file but is in a separate part of the file from the raw data that was collected by the sensor.
- What you see when you open the images on your computer may be one of several things depending on the application your are using to open them and the default settings that have been selected for that application. You may be seeing the jpeg preview. You may be seeing the raw data as interpreted by the application's default rendering profile.
Here is the good news: As long as you have the original .cr2 file you still have the information you need to edit the photo in whatever way you wish: B&W or color. The information you need to do either one is still in there. You just have to tell the application you're using to develop/edit the image to render it the way you want to.
How you can specifically do that is a little broad for a single question here without knowing exactly what application you are using to edit your images. If we knew what Picture Style you shot with and what application you are using as well as the default profile being used to open the images we would be able to help you in more detail.
Some of the most popular applications used to edit .cr2 images are Adobe's Lightroom and Photoshop, both of which use the Adobe Camera Raw engine under the hood to develop raw image files, and Canon's own Digital Photo Professional. Others include products from Corel (Paintshop Pro), DxO (DxO Optics Pro), Phase one (Capture One Pro), and One1 (One1 Raw).
I personally prefer Canon's Digital Photo Professional for the precise color control it allows and the resulting color that one can get from Canon .cr2 files using it. Many others prefer other editors. In the end it all comes down to which works best for what you want to do with your images.