Easiest question to answer first: Diet should optimally include frequent (every 3-4 hours) small amounts of healthy things, with plenty of protein and some amount of complex carbs. Specifically, try to get eggs (both the white and the yolk) frequently, like every day. Soy protein and whey protein (from dairy-based protein shakes) are also good.

Why protein? The buzzy, intense, effortful style of meditation beloved on this forum produces wonderfully quick progress, but can cause directed attention fatigue in people who aren't used to meditating so frequently and intensely. Protein contains amino acids that help the brain avoid and recover from attention fatigue more quickly.

Why carbs? Because it's very difficult for the brain to burn fats and proteins as fuel; it's designed to run on carbs. I'm certainly not saying to gorge yourself on chocolate and soft drinks! A bit of fruit several times a day would be great.

Depression warning: Many of the symptoms of the dark night somewhat resemble depression, but depression and the dark night are not the same thing! This is further confused by the fact that being in the dark night can trigger depression in some people, especially those with a past history of depression. The basic difference is that depression, in general, responds wonderfully to psychotherapy with a good therapist, especially when a well-chosen antidepressant is combined with the therapy. (Being on an antidepressant without good talk therapy is usually not very helpful.) On the other hand, the dark night will NOT respond to psychotherapy, or to antidepressants. It only responds to meditating until you've gotten the path you're working on.

So if you start struggling with depression during the dark night, please take care of it with a good therapist and, if the situation merits it, perhaps an antidepressant. The dark night itself sucks enough without being combined with depression.

I'll let more experienced people give advice about how to meditate during this self-retreat, since I botched the last one I did.

As to staying sane and not going mad. Do a small amount of standing meditation. This will keep you grounded. The primary reason people go borderline crazy or just suffer a lot with wacky energy problems and being spacey etc. is because too much energy goes to the brain. Standing meditation keeps it down. It will also keep you healthy and vital. Google zhan zhuang and do postures from there. The basic starting posture is wuji and you can rely on that solely or do another one you like after some time. Zhan Zhuang can be learnt on ones own with help of books and video because the postures are largely self corective, meaning that if you stand and meditative in them you will gradually find yourself compelled to stand slightly different, relax a bit here and then there, straighten up a bit etc. and this is all part of a process of the body naturally seeking the correct posture. If you just let go it works like that. do a minimum of 10 minutes but preferably aim for 20 minutes as you will be doing many hours of Vipassana. Some people stand for hours a day.

Second point. Open the microcosmic orbit. This is also in order to avoid excessive energy in the head but also helps you balance yin and yang in the body, avoid stagnant energy (not uncommon with lots of sitting meditation) and generally keep all your chakras fairly balanced. You don`t have to do it a lot. Just get it basicly opened and energy will run in it automaticly when you do other meditation.

Both the inner smile and secret smile ar good at smothing things out and keeping you balanced. They, especially the secret smile, also help your depth of meditation a lot. Six healing sounds is also a nice way to keep balanced. You could do one of them or all of tehm. Once you master teh inner and secret smile it is very easy to get into state. So in teh begining you spend perhaps 10-15 minutes on teh secret smile while afetr a while you can get the same effect in 2-3 minutes. So it is a rational way to spend your time as long temr you get a lot of effect for little time spent. You can find instructions for the secret smile if you search for it at thetaobums.com or in glenn morris` tapes. Michael Winn has good inner smile instructions. Chunyi Lin has a meditation Cd to help you open the orbit taht is considered effective and safe. I think he calls it small heavenly orbit though. You can find the cd on springforestqigong.

Do something to jkeep in shape and get in contact with your body. Anything will do but stuff such as yoga, tai chi, pilates, intuflow are better than spinning classes etc. for the most part as they give you more controll of your body, are better for alignment and also have energetic effects that aid your meditation project.

All of this is so that you can avoid suffering like BRuno, I and many others have with getting the energy under controll after it has gone crazy. If it goes crazy than it is much, much, mcuh harder to get it under controll. THen one might find that any meditation, even standing meditation adn the orbit is too aggravating to the energy and you might ahve to take the looong route of grounding through walks in nature, physical exercise etc. Once you have opened the orbit fairly well and built some earth chi and earth connection with standing meditation is very easy to ground back down should you space out temporarily. Also your vipassana practice will like be more pleasurable. Teh energy will feel better, your posture will be very good, less pains etc.

Best of luck