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Maybe you know all this but Thyroxine (quite often referred to as T4) is a hormone your Thyroid naturally produces. So I am going to guess the zap has resulted in you now being clinically hypothyroid which would explain the cold and tiredness.
Taking it (I'm going to guess it's levothyroxine?) can cause short term hair loss (and being hypothyroid causes hair loss too) but if it persists then get back to your doc it shouldn't be long term.
Turns out that they slightly zapped my thyroid gland while I was under the big machine, so it's not working quite correctly. It explains my sensitivity to cold and the tiredness, so it looks as if I'll be taking something called Thyroxine for the foreseeable future. One of the side-effects seems to be hair loss, so I hope the moustache survives...