I Have Been Taking Thyroid Meds For 3years And I

I have been taking thyroid meds for 3years and I get a lot of side effects that seem to be worse that the actual condition. My thyroid condition is not very severe according to the blood work. I am on the lowest dose of synthroid. I have also taken the generic meds. My Dr will not let me try the armour. So why keep taking something that is giving me so many problems?