Your body requires many nutrients to function properly and they cant substitute for each other. 3 drops of Lugols to be honest is hardly anything, its estimated 50mg will take 6-12 months to reach sufficiency (8 drops 5%).
That being said, maybe the Iodine did all it could do and now you need to stat adding other nutrients to shore up other deficiencies and/or get rid of possible intenstinal parasites. People with low stomach acid almost always have B vitamin issues, especially B12.