It's hard, but if you can get yourself to start some form of exercise, it will make you feel better. I've experienced this a lot. When I feel tired and there is no energy, exercise will give you energy. It is counterintuitive, but it's really true. Alternatively, when I feel like this I take a long hot shower! Seems to recalibrate and it feels great, especially in the winter when I tend to feel cold all day no matter what I do lol.