The TSH is slightly low with normal T4 and completely normal T3 -- with normal prolactin and the presence of menstruation, all this means it's not likely central hypothyroid (ie, the pituitary appears fine).
The slightly low TSH is nonspecific (but points towards mild/subclinical hyperthyroidism) and needs to be watched but would not likely cause heavy menses. Would complete the thyroid evaluation with ultrasound and possibly anti-thyroid antibodies.
So just for clarification...
You would still lean toward sub-hyper even though my fT4 is in the bottom 1/4% of normal with a low TSH? It seems my symptoms are more hypo than hyper. In fact I don't think I have a single symptom of hyper. I had a Mild brain injury to the back of my head a few years ago and have read that might cause hypopituitary.
I also forgot to mention that I never produced enough breast milk. Could that point to something?
Perhaps I'm way off, but I've read that low TSH and low-normal fT4 points to central hypo. Am
I barking up the wrong tree here. I'd hate to push for pituitary+hypothalamus tests if it doesn't make sense. Thanks Doc!