Depression?

I'm off today and I don't feel like doing anything. I forced myself to get up and cook something really quick. My thought was to clean and maybe go get some frozen yogurt. But as I'm taking my last bites I'm thinking about going back to bed. I always feel like this. What could be wrong with me? I don't like to think that I'm lazy because I will get things done if I have too. I just wish I had the energy to do things.