You probably need more sleep. If you have dark circles or "bags" under your eyes it could be due to lack of sleep. If you don't get a full 8 hours of sleep each night try getting more sleep and see if that helps.
Also if you have really bad allergies that could also cause it. My sister has bad allergies and she has this same problem. So far there hasn't been anything to make them go away for her.
There are some companies that make products that claim to help with the circles and bags but I have not tried them. Garnier Fructise has an "eye roller" that they say will help: