I have come to a realization, you have flushes that leave you feeling good and flushes that leave you feeling bad. They all still do good for the body. I have to admit that I felt very much like you did after my second and so I changed my 3rd. I haven't had the weakness with my 3rd or 4th. I had a real good dinner with lots of carbs for energy, I drank water right up to 3:30pm and switched to applejuice with the Epsom Salts . I believe that with #2 I became dehydrated and my blood Sugar dropped. Liver Flushes are hard on the body but they are better then being pumped full of drugs or going through surgery!!!
When did you start running to the bathroom? you may only need 3 doses of Epsom Salts . I gage whether I need the fourth dose by whether I am running to the bathroom by 5am. If I haven't gone by 5 then I take my 6am and 8am doses. Your weakness may have been dehydration and/or low blood sugar.
Somethings to try next time. Try a few more cleanses, give your body a chance to heal itself then get your levels checked again if you wish. It doesn't happen overnight but you may be amazed at how fast it can change. You may also need to do some dietary changes to lighten the load on your body, ie: cut out processed junk, lower meats and dairy, and eat more live natural foods. I found they really helped. Keep us posted!