I have a pretty good energy supply throughout the day. However for maybe the past week it's been a struggle to make it through a 45 minute workout. I just feel so drained and annoyed. I don't think it's boredom since I switch up my workouts consistently. Even afterward I just can't pull it together to do regular things. Also like most people around the 2-3pm hour I just get extremely tired. No, I'm not pregnant. Any clues???