I think JAB is on to something. My theory may sound a bit kooky, but bear with me.
I was going to share this before, but never got around to it. I'm pretty sure that the fish oil you're taking is probably loaded with naturally occurring Iodine and you're possibly getting detox symptoms by just taking it. Some people react very quickly to just a drop of Lugol's, so why not Iodine loaded fish oil? I was taking high dose cod liver oil at one time to ward off post partum Depression while weaning my son and after about six weeks, for the first time in my life (age 29), I had a sex drive (not just a little desire, but a strong one). Iodine makes hormone receptors wake up so they can start utilizing the sex hormones the body produces.
I put two and two together when I found out that one of the highest sources of naturally occurring iodine (other than kelp) is fish oil.