Question: I have … Hyperthyroidism or graves disease, multinodular goitre, cancer?

I would just like to know whether or not I could rule out graves disease as a cause of my hyperthyroidism. Or could I rule out toxic multinodular goitre or cancer?
I was diagnosed with mild hyperthyroidism in November 2015 t4=31, tsh=0.02 Before anti thyroid drug treatment I had a negative test for anti-TPO antibodies.
After anti-thyroid drug treatment (July 2016), My blood test showed I was now euthyroid. At the same time, I had a tshr antibody test, which was within range.
Now on 5mg carbimazole daily
I have a swollen lymph node in my breast which I noticed in December 2015 and is still there
I would just like to know whether or not I could rule out graves disease as a cause of my hyperthyroidism. Or could I rule out toxic multinodular goitre or cancer?