What symptoms do you have of thyroid problems?

I have the same and I generally find I can't concentrate very well, I feel the cold a lot and I'm more tired. My GP told me this was caused by it. Apparently it causes slowness in the mind and that's why I find it hard to concentrate. I find that it does tend to affect my life in a lot of ways because of the sorts of things it causes but I'm quite good at working around it now :)