You will suffer all those things if you are chronically dehydrated. With the way your body reacted from the Mag Cit is a sure sign that you are. Your body is bloating etc because of extreme dehydration. If you are malnourished, have kidney disease or are experiencing electrolyte balance issues you will continue to have this problem. You could try to correct it at home with pedialyte formula but if it does not clear within 24 hours you should see a doctor for an IV drip to get rebalanced before organ damage or failure.
The sell magnesium alone without the citrate. Twinlab makes one that is under 10 bucks a bottle for 200 pills and you get 100% of what you need daily in one pill. I would just take that instead and eat magnesium rich foods. Try eating Watermelon and drinking corn silk tea for your kidneys. Avoid chemicals sweetners at all costs as they can cause kidney stones. Avoid the mag citrate too so you do not get dehydrated. Do not mix dairy with black tea. The acid in the tea can make the dairy intake form stones. The mag citrate is not for long term use anyway. But food is! ;)