I seriously doubt that. It is far more likely that you had something else going on that you were not paying attention to. Most likely, you had blood loss either internally, or insufficient iron in your diet. Ferritin is a normal store of iron and there is nothing about the flush that would deplete iron. You were most likely deficient of iron and several other minerals before you started.
>- purges will deplete the body of minerals which are needed for good health
Yes, drinking lots of water will remove minerals. It is important to keep your normal mineral content up. Epsom Salt will help remove toxic minerals from the body by pulling water out. This is the purpose for taking it. It, however, does not remove a lot of iron and is not known to cause any significant decrease in ferritin.
>- Unfortunately no one told me that when I started this journey
Did you not bother to read the information out there?