I have never had a thyroid test out of the "normal" range, but I was showing so many symptoms (Thyroid UK have an enormous list, but they include dry skin, hair loss, weight problems, period problems, constant tiredness - you probably know better than me!) that my doctor agreed to treat me. I am now on 100mg ?mcg) of levothyroxine daily and I feel so much better, it's just not true.
It's worth pushing for treatment if it's affecting you. Sub-clinical hypothyroidism is not uncommon, and the treatment is not expensive.
As far as I know it's many years since the 'normal' thyroid range was determined. It wouldn't surprise me if it was done using male patients only - I'd be very pleased if someone can tell me I'm wrong on both of those!
Viv 8)