Hi linda,its just an idea but have you had a full thyroid test, not TSH. This maybe why your feeling this way,its not always mercury in the brain,and low thyroid gives brain fog,depression, cravings,to name a few.
If you are considering a test, make sure you ask yourdoc to test for a full thyroid panel,they usually only test for T4 which is bloody useless. I had to tell my so called doctor i wanted all the tests done, they havnt got a clue,
I wouldnt rely on the NHS, they are useless, you probably have some mercury inyour body but im guessing it has attacked your thyroid. dawn.