hair loss , lack of concentration

I'm concerned that I may have a Thyroid problem. I have been losing my hair for years. At times I have a problem concentrating, I forget what I'm doing. Sometimes while driving I can't remember where a road connects with another road and I miss my connection. My toes and fingers are always cold even in the summer. I have been sewing for 40 years and forget how to do something that I've done a million times before. I had blood work done 5 years ago and it came back borderline. The hair loss is very noticeable, my hair dresser is concerned. I will see my Dr. again in March. What should I tell her, I don't want to sound like a hypercondreiac. Should I see a specialist, if so what type. I am 58, overweight [I have been slowly losing weight since August- down 40 pounds.] Any info will be greatly appreciated.