30 years ago....enlarged thyroid, the over-activity and no treatment, doesn't sound right....... somehow.
I think you mean TSH was over 50 indicating an under active thyroid.
Thyroid antibodies suggest that your thyroid is undergoing some sort of change. Now 30 years ago and even today, some Endocrinologists feel that the presence of thyroid antibodies with normal thyroid blood tests does NOT require treatment........however others would disagree....matter of opinion.
It looks as though your levothyroxine dose is insufficient, but your doctor will decide that.