Most elite athletes have "de-loading" periods, it's not really neccesary to take a week off. However, depending on the athlete the deloading period can be anywhere from one week every three loading weeks to one week every six loading weeks.
If you are feeling VERY overtrained I might suggest one week of complete rest, followed by 2-3 weeks of a lighter load, working progressively back up to your previous best. If you aren't feeling that bad (just a bit under the weather) then I would suggest one week of deloading then moving to a 3:1 or 4:1 protocol for loading:deloading.