Hello! I am Dr. Aditya and will try my best to answer your question.
Galactorrhea or overproduction of milk is caused by excess
prolactin, excess
TSH, several drugs and some other diseases. But it does not seem to be your most alarming symptom. I am more concerned about palpitations and the fainting spell. Your TSH is raised so you are "hypo"
thyroid but your symptoms are the opposite of that! So your symptoms may or may not be endocrine in nature. Nevertheless I would suggest seeing a doctor immediately as your case needs detailed investigations.
I hope you are satisfied with my answer. Get well soon!
Next Steps
I would suggest checking your urine metanephrine and VMAs.