Selenium

I started taking selenium (200mg l-selenomethionine) last week in preparation for the Iodine protocol. The first couple days I was fine, then on the 4th day I got a horrible headache so I stopped for a couple days. I tried it again last night before I went to bed thinking I could sleep through it if my head started to hurt again....uh no! Woke up with a splitting headache at 5 in the morning...I hate taking pain killers but I actually had to take some tylenol. I never get headaches so I know it was the selenium :( I know it's an important co-supplement for the Iodine protocol so I'm not sure what to do now. Wondering if maybe I was really deficient in selenium and headaches are from taking too much to soon or something...? Thinking about maybe trying the other type of selenium, L-Se-methylselenocysteine. Any input?