Day 8 is like my nightmare day (all 3 times). I don't know why it is - probably simply a major detox day for me. The sleeping is usually an indication of the body working to detoxify. Hang in there - you're doing GREAT!
God bless and fast on!
P.S. For me things get much easier after day 12 - my body really starts to enjoy the empty feeling. Try to press through - it will be worth it!