I have been on a diuretic for several years for water retention. Four years ago, I gained about 13 pounds in two weeks time for no reason. I have tried everything, but cannot get rid of it. I have always been thin, so this is very significant. My doctor says it is because my metabolism has slowed because I am over 40, but I know it is impossible for that to happen over night. Because I am still not overweight by American standards, my doctor does not appear to take me seriously. Instead of losing the weight, I have gained five more pounds. I have been doing everything right and eat much better, etc., than I did when I was skinny. My clothes do not fit. Could it be the diuretic use having an opposite effect? Please note that my thyroid was test and is fine. This is making me crazy. I have tried everything since 2009, and, no matter how much I exercise or diet , I will only gain weight. In fact, when I work out, by day s end, I actually become swollen and weigh more. It is insane. Until this happened in 2009 (during a tw0-week vacation in D.C.), I lost weight very easily. Help!!!