Strange week

This whole week seemed strange, nothing unusual happened but things I normally can handle on a daily basis seemed like the hardest tasks. My body felt heavy, I was mad for some unknown reason. I couldn't shake off this feeling, and everything just irritated me to no end. Had trouble getting out of bed, and could not handle minor issues at work. It feels strange because normally I have a lot of energy, and feel positive. Starting to do better, but this low mood threw me off because it came without a reason I know of.