When I was in second grade, if you did your work and were behaving, you could go to one of several centers in the room for delightful reward playtime.
One of the centers was a showbox with about a quarter sized ball of mercury in it. You could pour the mercury in your hand and wiggle it around, you could "splat it" in the bottom of the box with your fingers and watch the little beads of mercury scatter and then come back together in one piece, etc.
All the kids in the class had hours and hours of free time with that mercury through the year, as bizarre as that is - and hair raising.
I think you're fine.
I'm sorry, I realize I had been flip with your question. I just hope you don't get overly worried. It doesn't seem like the mercury would cling to your sink, but it's actually scary that it got into the water system, and shouldn't have been thrown in the city garbage.
Best wishes, I hope you feel better.
I too played with the mercury in the themomonters when I was a kid. It was so much fun. That was about 30 some years ago.
My son too has an aniexty disorder and OCD. I understand how you might be feeling. I would call your Dr. tell him/her what happen and ask for a heavy metal test. I am sure you are fine but seeing it in writing just might calm you about it.