Sleep can be managed but for me is always a challenge. Medications can help if it is a long term disturbance. But what everyone suggested is right on target. Feeling exhausted all the time is both from your emotional work and maybe over sleeping.

The focus issue, as things settle down emotionally your focus usually returns. When I get that way I try to adjust myself to accepting it is what it is and working around it rather than get angry with myself. Build in the frequent breaks, plan them as productive breaks. See if changing the activity method will keep your focus on the objective. OK, gobletigook - If you are studying for an exam by reading notes or outlining a book as your focus shifts change into making flashcards of the material. Changed activity continued focus on studying but because it is different it may keep you on task a little longer.

Shift your plan of attack frequently and it may help to keep on track.

Break your jobs into several tasks to shift from -

Doing Bills

Sort the Bills
Total the Bills
Balance the Check Book
Address the Bills
Make out the Checks
Look at the Budget