What is the likelyhood of me having an overactive thyroid?

When I was younger ( around ages 5-13 ) I was very, very skinny. So skinny that you could see my ribs and other bones under my skin. I was able to eat ANYTHING and everything and I would be hungry all the time. I was often called greedy and was told by people outside of my family that I ate way too much. I also got comments from people about my weight. People asked my mother if I I had some kind of illness because I was so skinny. When I was 12, I was 5'1 and weighed a mere 85 pounds. I never saw a doctor for it. when I got into my teen-aged years, I gained weight. About two years ago, I noticed strange symptoms starting to appear. for a few months at a time I noticed i would lose weight without trying at all. I would drop as much as 15 pounds for no reason and I would also be very tired and very hungry ALL THE TIME ( same symptoms as when I was younger and very.very skinny ). After a few months, the symptoms would disappear ( except it would take a long time to gain the weight back ) and then reappear. If I touch my throat, I can feel my thyroid easily. I also have a history of miscarriages and irregular periods.