WHy do I always have bags under my eyes?

I am 13, will be 14 this year and I seem to constantly have bags unnder my eyes. I have not been eating the healthies in the summer but have not noticed a change wether I eat healthy or not. What can I do to make them go away? And they are not just a figment of my imaginnation. My friend has also noticed them. Please help, 10 points to best answer THANKS!