What do I do to make my hair stop falling out!?

Ok, so I bought a bottle 10,000 mg of biotin and I take them once a day. Can I start taking them twice a day? Also, Im going to buy Mane-n-tales or a hair regrowth system. My hair use to be so thick and curly, not its thin and curly. No volume whatsoever! Whay other things should I do to make it stop. It use to be falling out like crazy, now its calmed down alot! I went to the doctor and he said it was Alopecia...