Iodoral and weirdness

Hi everyone!
I'm new to the forum and to iodine, and I guess I'm looking for some reassurance. I started taking 12.5 mg of Iodoral about three weeks ago for breast pain, which has always bugged me but is getting worse as I get older (just turned 45). The results were incredible and quick- within a week, my cat could step all over me without me wanting to scream, lol. But the downside --my period came almost a week early and is still going strong 5 days into it. Is this common on Iodoral? I don't want to stop taking it...but I also don't want this every month, either. Can anyone commiserate or advise?