I went to one years ago - one who was truly talented, and she really fixed me up. Most of my allergies (which were bad at the time) are gone and have stayed gone over the years because of her. They're not always easy to find, but definitely worthwhile. If you're that concerned about the doctors (and I would be), I think you should look into it, remembering all iridologists are not equal, so listen to your intuition.
Regarding your liver, given your heavy detox symptoms, it definitely sounds like your liver is a bit backed up. My suggestion would be to look into the following:
I use Solaray formula sp-13 fairly often. It has milk thistle, dandelion and artichoke, among other things, all known for being great for the liver. If you're at all concerned about your liver, you have to take these herbs. Given our livers are under constant assault, I think taking these should be automatic (with periodic breaks).
Another is a liver flush.
Another is spirulina - very nourishing for the liver.
Another is wheatgrass juice.
Another is taurine.
Another is essiac tea (also good for pancreas & kidneys).
Another is the mini-beet protocol (beets will kick the ass of a lot of bad stuff in the system).
Lastly, have you considered regular short, controlled water fasts? If you really want to help your liver, one very good way is to stop dumping stuff on it and let it catch up. I know of no better way to do that than a water fast. Some do orange juice, juicing, and tea fasting, but water fasting is king. You might want to check out that forum and read the Shelton stuff. Start slow and see how far you can go over time.
If you drink alcohol, stop for a while. Completely.