Have a couple of free books on me 
The first one is easy reading, the second more of a reference book. I know of these thanks to Chrisb1, who regretfully is not here due to a bereavement.
I am on my second fast, see my very recent post titled day 2 of 11 day fast. I drove 400 miles recently, I am never tired, and don't feel spaced out.
On my first fast, I had the desire to drink coffee even though normally I drink it rarely, but I just weathered it through. On my second fast I treated myself to a coffee from a McDonalds drive-through on the first day, I thought "sod it, it's Christmas", and I had a long drive ahead of me. But from my previous Atkins dieting, I think you will probably get a headache for a day or two, as the caffeine addiction wears off. For me it was regular tea drinking that caused the headaches.
No hallucinations, apart from self generated dreams, eg I visualised a delicious bowl of fresh salad with home grown tomatoes on my first fast, yum yum! Oh yes, you get to appreciate healthy food when fasting. But hallucinations, no. Not for me anyway, and I have never heard of such a thing.
The worst thing is the boredom. Anyone who fasts will be surprised how much their life revolves around food. But on my second fast the boredom is not so bad.
Good luck, I wish you success.
Fasting is very subjective what works for one person will not necessarliy work for the next so its best to just take a plunge ACTUALLY fast and see what works best for you.
To satisfy your curiosity here are some answers to your questions.
So if i fast, will i be able to function, go about my normal routine?
Again it takes you actually fasting to know if you PERSONALLY will be able to function. My very first fast was water only for 23 days and I was able to function, work, drive. Then a 2 week juice fast I was functional, but I've also had a fair share of fasts where I was mostly weak, irritable and spacey.
So do many of you experience mental detox, old emotions that resurface etc.
I've read that fasting not only cleanses/heals your body, it does more.Its said that old emotions can resurface etc. In my experience I've found it true especially during longer fasts. Also you have a lot of time to idle away when fasting so I guess one now has time to deal with those issues they are usually too busy to confront.
Is it common to get hallucinations while fasting? And how do you deal with that?
I've read of people having weird dreams during fasting and experienced this a lot on a fast a dew yrs ago, luckily my friend had a book that interprets dreams so it became fun trying to figure out the symbolism of the dreams. So rather than worry I dealt with it by turning it into a fun activity. Oh yeah I just remebered this same fast of weird dreams, I was supposed to interview for a job and the night before I dreamt the prospective employer had/was planning on kidnapping me... I freaked and wanted to cancel but my friends insistef I go, nothing happened. I do remember this fast 24 days for notoriously having been about weird dreams.LOL
So hope that answers some of you questions, and sure I'll join you I'm on day 2 today.Good luck and keep us posted