With your FT4 low end, you may need an increase in meds (if you are on them).
Get yr labs done as you must be feeling like cr@p.
Yes, sometimes Iodine can make TSH go up. Your FT4 is low end and you may be feeling tired, sluggish and constipated along with the lovely brain fog and leg cramps.
Quit the kelp for a few days. If you don't feel better, then demand these tests:
TGab and TPO antibodies for Hashimoto's auto-immune thryoid disease, which causes 90 percent of hypothyroidism in developed countries. If so, then please be advised that iodine and kelp, etc, can be worse for an auto-immune flareup. Read the book: www.thyroidbook.com for further research.
FT4/FT3 to determine your thyroid levels.
Unfortunate, you didn't get the FT3 test done because that hormone is more active than FT4.
:) Tamra