Why am I so tired....?

Why am I so tired? I did not go to work today instead I slept basically all day. This sucks. I should not be tired I am a young man. I should be up and full of energy. I have to start going to bed earlier and being more healthier as well. I hope there is nothing wrong with me and my body was just run down. I will get a good sleep tonight and be in bed earlier then usual.