linda, in your position i would go back to the doctor who prescribed the thyroxin and ask her/him to take me off it asap.
after a time it is increasingly difficult to stop using thyroxin, because the body rebalances taking into account the supplementation. over time you need increasing doses of allopathic drugs - the same old story.
if you find a good homoeopath they will be able to treat underactive thyroid, but this is less likely to be the case if there is thyroxin supplementation.