Hi I have been reading everyones post for information, I've just been diagnosed with hypothyroidism underactive been put on 100 mcg level. Tsh was 100 and very low t3 I think, thing is I feel like I'm really ill. Weak, aching muscles. Freezing cold. Brain not working as should! Called the doctors and they don't seem to have an answer if this is what to expect, need to get well as have a son and daughter to look after :((( thanks nat.