Yep, the crabbiness, frustration, headaches, tiredness, all of these are detox symptoms. Sounds like this is the best decision you've made in a long time! :^) I would recommend going 14 days and then seeing if you can go another 7. I didn't really start to feel good until day 12, and there are real benefits to fasting a lot longer than 10 days. There isn't really much physical benefit in doing the Master-Cleanse for less than 10 days as the body doesn't really get time to do any serious healing work in less than the minimum time. But remember, this is the minimum recommendation. You can safely stay on the Master-Cleanse up to 40 days, and you just have to read Somer's posts to see the awesome benefits of a lengthy fast.
The sore throat is also a "symptom" of fasting. In fact, it's common to get a cold in the beginning stages of fasting as your immune system becomes a bit more susceptible to viruses on the outset. Lots of water and rest (so the body can effectively detox) is all you will need to feel better very soon.
As to 'special' benefits, please find the recommended/newsletter post of Pepe's on the stages of detoxification. It is MUST reading for everyone feeling discouraged. Remember that your body is doing work that it simply CANNOT do while its energies are diverted to digestion. Your whole body is going to thank you for this decision to let it rest and heal. There are some great internet sites which explain the benefits of fasting as well and I recommend you read everything you can on the subject. There really is nothing like it for good health. God bless and FAST ON!! :^)