Re: really confused
That's bull. For ONE whatever you do, do not take the RAI pill while nursing. I believe you can hurt the baby. TWO, you can get an FNA (Fine Needle Aspiration) which is a biopsy to test that nodule and see what they have there. If there is no cancer, which is probably the case, then no big deal....you should be able to finish nursing. If it is cancer, then you have some decisions to make obviously but at that point, breastfeeding might have to take a backseat to the cancer.
Its still very early in the game. It sounds like it might be Graves' Disease or a hot nodule, which is a cyst that is capable of mimicking thyroid cells and produces a lot of hormone, sending you hyper.
With regard to your mixed signals and having hypo symptoms, many symptoms overlap. With a TSH that is virtually undetectable, I would for one want more tests. You need to have another TSH, Free T3, Free T4, Thyroxine, Total T3, Thyroglobulin Antibodies and Thyroid Peroxidase Antibodies and the TSI (Thyroid Stimulating Immunoglobulin...I think...just call it TSI) test to test for Graves. Once you get these additional tests, you will be closer to knowing what's wrong. Everything works in combination with the others so getting all those tests at once is important. You will need to be persistent with your doctor to get him to order all those tests probably.
Next, with regard to the stress factor, absolutely can you get your first "onset" of the disease under times of hardship. For me, it was the birth of my son. 3 months later, my thyroid crapped out. You need more tests as I mentioned above and yes, tons can be told without having to load you up with radiation.