80 % of your immune system is in your gut. 80% of your serotoinin is also in your gut! Your gut is where it's "all at" and if it there are problems going on in it you will feel pretty crappy.
Dr Mark Hyman, among others, said that ALL diseases are caused by bacteria, virus, and parasites. As you can see by the attached list, the intestines/colon is a favorite place for them to hang out. And I don't think this is a full list. There are many cell wall deficient Bacteria's that are parasitic that are NOT listed, babesia, erlichia,Bartonella, and more.
http://en.wikipedia.org/wiki/List_of_parasites_(human)
I Think you should start with a deworm/anti-parasite program. Because we bring them in on our shoes and in our food and water, we should be de-parasited every 6-12 months, just like we do with or pets and livestock.
Black walnut hull, wormwood, and home-ground cloves will rid you of many parasites. Look online. Again grind your own cloved from store bought whole cloves because the power leaves them soon after grinding. Put the powder in 00 capsules from your health food store.
Samento and Cumanda will rid you of much bacterial parasites. 2 drops 4 times a day. one month for each year being sick. So if you've had bartonella or Bb bacteria since you were a kid,(as many have) you'd be on it for years.
Here's another site to check out. Eye opening:
http://www.marshallprotocol.com/forum32/1263.html