Hair Loss

I am a 30 year old female, 3 children under 8, and I started lossing my hair suddenly about a year ago. My first wierd symptom is that  I woke up one morning with puffy circles under my eyes which really freaked me out. Then about a month later my hair started noticibly falling out. I've tried everything! I do know that I have thyroiditis now but I've been on the thryroid hormone for about 8 months now. Why is my hair still falling out? I've lost 3/4 of my hair. I have to wear hair pieces. My hair when group together is the size of a pencil round. I don't know what to do. I feel like I might go bald. It won't stop falling out. I do have a twin brother and he has really thin hair but he is a heavy drinker so I contributed it to that. My hair loss was so sudden and in excess. Does not seem at all normal even if hereditary. Help!!!