You asked what you've done wrong, so I'll offer my opinion. (I am not a doctor or licensed medical practitioner of any sort.) I don't know how many flushes you've done, or what your other experiences are, but I'm going to speak as if you were a beginner, because I don't know any better, and what I'm saying is vital for any beginner to understand.
I note in another message that you comment that you once did a liver flush without using the Epsom salt drinks. From simply this one statement, it's pretty apparent that you had no business doing liver flushes at that time. As you pointed out, you've read some of Moritz's material and realized that you should have done much more prep work. That's an understatement.
One problem that we have here at CureZone is that some folks manage to see great results by doing the programs haphazardly or "their own special way", skipping steps, doing things differently, whatever, and for these folks, it's great, but when they start telling other people that the altered procedures is how other beginners should do it, this is where the danger lies. This laissez-faire attitude comes back and bites everyone else, because then we have folks running around giving horror stories and blaming the horror story on "the liver flush" rather than the specific deviations from a standard liver flush that the person did. In other words, blaming "the liver flush" for the horror story is kind of like substituting salt for sugar, corn starch for flour, and leaving out the eggs, and then complaining that the cake recipe is flawed when some awful mess comes out of the oven.
Serious illness from the Dr. Hulda Clark style liver flush comes from incomplete parasite cleansing (assuming that you've done the procedure correctly, including Epsom Salt drinks). That's it. Parasite flushing can be incomplete for a variety of reasons, not the least of which is insufficient colon cleansing. Other possibilities include continuous parasite reinfection, continued exposure to parasite-friendly toxins, or simply not doing the parasite cleansing program long enough.
It is vital that the prep work be done before doing liver flushes. Now, if you are healthy, if you know yourself well, or if you just know that you don't need to do those prep steps, then you can probably get away without doing them. It does work for some people. (Then they come back here and encourage others to just go straight to liver flushing... I'd like to smack them, sometimes... They mean well, but something about hell and paved roads and good intentions keeps coming to mind.) That is the exception, however, and not the rule. No one who does the full prep work, however, and who does the process by the book, comes back and reports horror stories. Slow progress, sure. Disappointing results, sometimes. Great results, sometimes. Strange things in the toilet bowl, sure. Pictures of stones sometimes. But horror stories? No.
The only time I've ever personally experienced the horror stories is when I've (wildly) deviated from the plan, and my horror stories include giving myself full blown gall bladder attacks, so I've suffered for my experience on the subject and know a little about it. (Search for my name in the archives if you're curious.)
Different well known pros in the field have different preferred methods. If you want to be able to create your own specially tailored version, I suggest you study lots of different pros, see what they have to say, find what they have in common, find out why they recommend what they do, and then explore the archives and see what others have done, what successes and failures they've had. Then tailor something to you. (Please, no one else should need to suffer through a horror story. We've already done it enough. I have already done it enough. Learn from my mistakes! Much less painful that way.)
For example, there are a wide variety of ways to do colon cleansing. It doesn't really matter, in most cases, which way you do it, so long as you do it and do it first (with extremely rare exceptions -- if you have doubts about your ability to do colon cleansing, then you're probably one of those exceptions). Some folks like enemas and colonics, some folks prefer herbals or teas, others like magnesium and oxygen supplements, some go for the ol' daily quart of warm salt water, still others prefer juice fasting (say, prune and apple juices), and yet another group of folks swear by psyllium husks and bentonite clay. Many folks use a combination of these methods. There are probably others. So the how is not so important. You are free to experiment here, but you can probably already guess that some methods are going to appeal to you more than others. Try them. If they work, great. If not, stop and find something else. If you're unsure, pick a pro that appeals to you and follow his or her program to the letter. No deviations. Remember the cake recipe?
As you do this, you'll learn more about how your own body works, which is valuable experience for helping decide what to do on subsequent steps. When you deviate from a program, however, please realize that, until you really know your body well, you're always taking a risk that you might suffer as a result. The "pros" lay out their programs with specific steps for a reason. Learn your body, and learn the reasons, and you'll master your health in no time.