I go back & forth with fatigue. I can sleep all day and still be tired. I also think the weather plays a big roll. Here it has been raining & dreary over the last week. I am having a very bad week. Could be the weather or pain you are having. You mentioned you are having quite a bit of pain right now. When I hurt worse it really drains me emotionally & physically.
If it doesn't get better, maybe ask your doctor for something that might help. I know others who take something to help stay awake and alert. I haven't had any luck with anything helping, but people respond differently. Good luck & hope you start feeling better soon!
Hugs,
Springfling