I have not heard anyone report problems at your dose, which in my opinion is very low. Generally speaking, the only posters I have seen reporting problems (regardless of Iodine dose) are those who don't take the support protocol (selenium, vit C, magnesium, ATP cofactors, Sea Salt ).
As for Iodine accumulation, my only fear thus far is not enough has accumulated in my body. Iodine is an essential mineral that your body needs. And at much higher doses than the RDA. Your body knows what to do with it.
Based on your original post ("Still not sure how, but I got in a routine of taking 6-drops/day of Lugols 1/2 strength (together with Potassium salts) for around 6-7 months") I get the impression you were very casual in your approach, and it's really not clear if you made an informed decision. If you are serious about understanding the protocol, check the links at the top of the page. That should help put your fears to rest through education.