Nodster - Just do what you feel like doing. Fitness wise you'll have lot nothing from a week off. Don't put pressure on yourself to do anything. There are plenty of opportunities to run a marathon. Look after yourself.
I seem to be returning to form. I did 9 miles last night at 8:31 m/m average pace and then my cutback week LSR of 13 miles this morning at 9:09 m/m average pace. Far too fast for a LSR, but it didn't feel like I was pushing! The calf must be getting better after all.
Heidi - Right now is when I'd be expecting to feel most tired and generally pissed off with the training. You're well into the training schedule, but there are still a few hard weeks to go until you start to taper. I think mentally it can take it's toll as much as anything.
If you feel physically ok while running then I'd stick at it and not drop any runs. Fighting this mental I want to give up feeling is what gets you through that final few miles of the marathon. You're training your mind to push through the tiredness, as much as your body. If you're feeling really worn out though then maybe dropping a couple of runs from a cutback week and coming back fresher might be an idea. I generally work on a push through mental wanting to give up, but take a rest if I feel the body is struggling.
If possible try and have a few early nights. If you feel hungry all the time then make sure you are eating enough and that you are eating what your body requires for the training you've been doing. I'm not the best at giving advice on the food part, as I'm a greedy sod and the mere mention of food makes me want to eat!