I had bloating the first week on iodine...and then I was taking a minuscule amount-380 mcg. After getting to around 7.5 mg slowly, I then made the jump to 125 mg and didn't experience any bloat, etc. Just more energy. This week I've been experiencing some fatigue and headaches, but I'm taking Dr. Venessa's Liverclean pills to help get more toxins out, so that could be why.
Are you taking the co-supplements...i.e. Vitamin C, Magnesium, SELENIUM, ATP co-factors, and plenty of salt flushes/salt in water? These are key when taking iodine.
Also, are you taking milk thistle, NAC, for liver support? If you are not taking these things, your liver/kidneys could be having trouble filtering all the toxins out. Make sure you are also keeping hydrated and having regular BM's.
I've had digestion problems, too, which are now getting better. I take Cal-Mag Butyrate capsules which contain butyric acid, and occasionally I will take digestive enzymes and Betaine HCL. You may want to do the same.
Taking more Iodine has been working, in my case. You will find differing opinions on dosages on this board. It's all in experimentation and what works for you.