Mid cycle period after total thyroidectomy

So last week I had a total thyroidectomy, on CD 8. Of course they have me on cytomel once a day, I'm also taking antibiotics. Well on CD 12 I had some bright pink spotting, didn't really think anything of it (possibly ovulation coming). But yesterday, CD 14, I started heavy spotting and now I'm having what appears to be a full on period! WTF is going on? Has anyone here had a total thyroidectomy before? Had this irregular period with it? It's irritating because my cycle had started to even itself out over the past 6 months, now this!