Hi fiona, i too have been prescribed anti depressants, my doc laughed at me when i said i wasnt depressed.
I also live in the Uk and have been diagnosed with CFS.
I never got tested for mercury, but because no doc could tell me what was wrong, i put it down to mercury.
I have had my amalgams removed now and only have a few symptoms left, where as before i had over 30.
Im still very ill though, it takes a while to get better.
Are you on a candida diet, sometimes going on this diet can eliminate some symptoms.