Hi. I have no idea. But the nurse may not know. (I am an RN.) Seems to me a set of labs is indicated, especially a CBC (cell blood count) to know your white blood count (WBC.) That would give information that can help rule out a very rare reaction, and a serious one, to methimazole. Agranulocytosis can happen, but I have no idea if it is a a possibility after you have been on the ATD for as long as you have been taking it.
As you already realize, that is a pretty big knee jerk reaction to stop taking your methimazole cold turkey. I certainly do not recommend that. But I understand your frustration, as well. And as you have learned from how you feel regarding hyper symptoms, one can hypothesize that you are still hyper without the anti thyroid drug.
*Do you have a fever? ARe you continuing to feel fine?
I think if you get really sick this weekend, and I mean REALLY sick, fever, etc., so that you are worried about yourself, you can consider going to an ER, but otherwise, I would call the docs office first thing Monday morning. How long has it been since you have had labs? Do you have a copy of them?
And, of course, it is possible, that it is unrelated to Graves’, or that you had something whacky that is over now.
Another consideration, depending on how your doc’s office works, is that you can call the on-call, describe your problems AND your meds, (be SURE to take your temp) maybe even mention agranulocytosis as a rare side effect, ask if you can get some labs drawn this weekend.
Of course, I am just thinking as I am typing, and definitely not a doc, as you know. But some things to think about.
Shirley