The problem is thyroid levels change day by day so one day you may have normal levels other days you have lower....I have hypothyroidism and it took me 3 months of being really sick sleeping for 17 hours, not going to the washroom, gaining weight, not eating, losing my hair and severe severe depression for a thyroid test to come up as being low and when it came up as low boy was it ever low I was actually admitted into the hospital.....But the first 2 to 3 tests I had received when I first started feeling sick came up as normal.....I have a long family history of hypothyroidism so my doc kept sending me for tests knowing that I was at higher risk of having it.

Keep at it if you are convinced it is your thyroid, but make sure that you get everythign else checked out as well. There may be something else wrong