I would search adrenal fatigue / insuffiency, hypo thyroid; to find it most probably related to sjogrens, low libido, Depression etc. then start to adress these two glands first.
In my case (and a few others I know over here) I couldnt tolerate e.g vit B or A for a while, until my adrenals was up to par. Now no problem with it.
If you chose to take Iodine (high dosages like 50-100 mg; read the vwt Iodine forum) this may cause a detox period, for me it took 3 months. The symptoms of detox will differ related to the issues you have. For me it caused intestinal havoc, flare up of IBS.., for others it gives different symptoms.
A good friend of mine took iodine/boron/magnesium a few years back, but couldnt take the detox symptoms (for her, pains, flu-like feeling), so she went back to anti-inflammatory medications, painkillers. It worked for a while, but now it all strikes back; she put on 10 kilos in 10 months, lots of pains, knees are like a 80-years-old, osteoporosis etc. (she is in her early 40-ies, and excercise alot) I doubt I get her into Iodine again, as her doctor said she had enough of everything. Blood tests.
Boron; quit for a week or two, then see if you can tolerate a small amount. If not, wait a month or two. Work with the other issues. With iodine, I would go for a high dosage, as it push out the bromide. 400mcg is just a drop in the ocean IMO. Also search fluoride, often recommended with sjogrens (STAY AWAY). Related to calcium (boron, magnesium) For sleep issues, it is a must read. http://fluoridealert.org/issues/health/pineal-gland/
Search, read, try,fail,retry; education at its best:)