Push is coming to shove. Urgent situation. Overwhelmed, help please.

My situation is getting pretty urgent, if I don't get my problem "fixed" in a month, the doctor says that I will need a colonoscopy. I am only 19, and I don't want to be dealing with this so early on in life. At around 8 years old I was diagnosed with ADD and have been on over 14 different meds for ADD, Depression, and Insomnia. I took myself off all medication to the disapproval of my parents and doctors in 2003. I have been comping relatively well with my concentration struggles and seem to be doing OK. My overall constitution is not great. I sleep 4 hours a night and have a lot of allergies. I have terrible constipation, I evacuate every 4-5 days. Bloated, it hurts to have pants buttoned while sitting, and I cant sleep on my stomach anymore (hurts the back too). I'm 5'10/140 LBS/Male (with a weird distended gut). I drink plenty of water, get enough fiber, and stick mostly to uncooked fruits and vegetables/ whole non-wheat grains, nothing seems to help.

Ive been lurking on this board and doing research for about 5 months and have learned a ton. My friend has used the system provided by
http://www.healthwakeup.co.za
so I am copying their plan (with a few modifications, as I cannot get the exact supplements provided), plus it ships from South Africa and I live in Los Angeles.

Basically, you don't eat solid food for 7 days, you take a bulking laxative (psyllium based) with all kinds of supplemented nutrients. I suppose it is a Water Fast with nutrient support w/ hydrotherapy twice a day (5 gallons each time) (lemon juice added). It is a fairly strict routine, but with G_d's help it will work out.

So I have to decide between a colema board & bag vs. a device that sits IN the toilet and has a tube going up (THIS
http://www.homehydrotherapist.com/).
This would be the ideal choice except that the "tank" is only 2.5 gallons (I need a 5 gallon tank), everything is plastic (I have no quality assurance), and I could not locate any people who have used this device (private newish MFG I suppose.) An upside would also be shipping time, it ships from California and it costs less than any colema board / bag I have seen. Costs $120 shipped.

I also decided to purchase a reverse osmosis 5 stage + UV + 4 Gallon Tank (100 GPD [Gallons per day]) water filtration system on eBay for $200 shipped (I am technical minded, anything involving computer programming, building, and scientific concepts come easily to me plumbing wont be an issue), but I don't know if it is quality (it got somewhat good reviews, has quality filters, and the filters are very reasonably priced).


Progress:
1. Was to work out the supplements, I need certain amounts (mg) of nutrients and different pills/companies come divided differently. The plan is to get all the supplements from two shops on Amazon (to minimize the amount of separate orders to get my stuff), plus Amazon is giving huge shipping discounts at the moment.
-Done. Open to advice.

2. Selecting colonic Device. I think I want the aforementioned
http://www.homehydrotherapist.com,
but I want to know what you guys think (bearing in mind my thoughts about it), if you have any recommendations, personal experiences relevant/possibly helpful to me. If I do need to deal with the 2.5 gallon tank I suppose doing a refill midway isn't so bad. I don't want to have to deal with modifying its pluming or attaching a bigger tank unless there is a straightforward and easy solution.
-Deciding

3. Getting the water filtration device. I was originally going to purchase a 73 Gallons of distilled water to use for the 7 days (10/day +.5 for drinking). My local water's TDS (total dissolved solids) is 200ish (not too bad, but its got chlorine/chloramine (yes I know that R/O [Reverse Osmosis] doesn't kill chloramine) and flouride which I want to avoid, and I want a water filter anyways for lifestyle changing reasons.
-Deciding

If anyone has any info that may be of use, please respond.

Thanks for your time,
Siderealion