What Causes Tiredness, Weight Gain And Eczema Patch On Foot?

Extreme tiredness and sudden, unexplained weight gainDespite following a reasonably healthy diet, I have put on roughly a stone a month since January. I am constantly tired, have become very forgetful and clumsy and my skin and hair have become excessively dry to the point that I have developed a eczema/dermatitis patch on my foot. I also bruise very easily. I struggle at work because of the tiredness and when I'm not working, all I do is sleep. My thyroid was checked in March and was okay and a diabetes test was also fine.