That's interesting. I was also an office admin (for a church). I wanted to rock that job (and I did) because I loved the idea of working for my church. I was desperate for work and I know the feeling of not wanting to disappoint people. I was good at everything I did there and because I was good, they kept slowly increasing my workload almost without being noticeable. I didn't want to complain and I felt very fortunate to have a job I loved but I started to feel like I was constantly juggling balls and I had to make sure I didn't drop any of them. Even so, I managed to stick it out for 4 years and there were some things that definitely helped me "get by."
1) If you can sleep and feel refreshed when you wake up, it's a good sign. If not, then it helps to make sure you get about 20 minutes of meditation in once or twice a day. Even if you do sleep well, meditation can be crucial to "refill your bucket".
2) Before bedtime, take a couple hours to do things that help you "unwind." Nothing stimulating like computers or action tv shows or reading murder novels or stimulating phone calls or eating large meals. I would shut the tv down by 7pm and read calming books, took a bath, did some yoga, meditated, things like that.
3) I tried to get some kind of body work at least once a month. Accupuncture and naprapathic was very helpful.
4) I stayed away from sugar and anything stimulating like caffeine (tho some people with CFS or CFS symptoms can actually be helped by a little bit of coffee. Drinking any amount of alcohol, however, I think taxes the adrenals. It always made me feel much worse. Also gluten made me much worse.
5) When I would get to work in the morning, I was lucky because I was usually alone for a while. I took about 10-15 minutes to just sit and breathe with my eyes closed and the lights out. I focused on my out-breath and during my exhale I repeated the word "oooouuuuuut". (out) I let all other thoughts just set aside and that really helped me begin my day feeling calm and steady. I think that was one of the most helpful things I did. If you're not alone in your office you can come to work a little early and spend 10-15 minutes in your car parked someplace no one will bother you and do the exercise.
6) After a car accident I knew I needed help and adamantly requested an admin assistant. It made sense to the Board. I was the only one running the office and my recovery time from the accident started to drive home the need for a back up in case of further illness or a death in the family, etc. As it turned out, the person they hired to assist me became the one who took over after I became too ill to continue. I was very grateful for that. I didn't feel like I was leaving anyone in a lurch when I suddenly woke up one morning and couldn't even leave my bed.
I think if it hadn't been for the car accident, I may still be plugging along but in some ways it's been a real blessing that I had the accident. It occurred because I was so exhausted that I ran a red light. The incident forced me to stop pushing myself. Now the current admin at my church is dealing with a recent huge flood so there are flood issues, insurance company nightmares, renting a temporary church space (so she needs to go back and forth while our church is being renovated). Even though she has an assistant, sometimes she's there till midnight! That would have been me... ugh!
Anyway, there are some tips there that may help should you decide to keep working.