I think you should consult with a doctor as people have said. You should also consider trying something that breaks your current schedule because it isn't work

I think you should consult with a doctor as people have said. You should also consider trying something that breaks your current schedule because it isn't working for you. Every year I try something new. This year I have been going to sleep before 10pm and get up at 6:30am. This has been a sort of revelation for me in terms of feeling better throughout the day, but it might not work for you. It sounds job related to me. You should force yourself to get up for more frequent drinks of water/walks around the office and, whether you want to or not, you should probably stop using a computer in the evenings perhaps a few days per week. See what that does for your mood. If you do this for 3 or 4 weeks and nothing really changes, then you can explore other reasons for your exhaustion. My routine requires me to walk about an hour a day and I exercise once a week (not hardcore by any means). That might help as well. Anyway I can relate. I often feel that way but I think it is due to work pressure.