What Causes Severe Hair Loss?

Hi, I m really sorry to bother you but I m hoping you can help me out. I ve been getting laser hair removal treatment on my legs for the past two years. In 2014 I noticed that my the hair (on my head) has started to shed dramatically. It s gotten to the point where its way more than 200 strands a day. I ve had medical tests done and they came out normal. I want to start taking biotin supplements but everyone has different opinions about whether it can interfere with the treatment. I really hope to hear back from you. Thanks for your time.