Simmone,
I have gone through the same thing. It's very scary. I've gone through periods where my hair has just fallen out in handfuls while I was standing in the shower. According to the doctor any type of stress, change in diet or weight loss can cause that cycle. So, I went to a nutritionist who suggested the following for me.
1) MSM, because it helps your nails and hair to grown faster... it really worked in my case
2) Enzymes, because they break down the nutrients in food so that your body will digest it better. If you're taking it vitamins from food and your body is digesting it. It doesn't help the body.
3) a good Hair Vitamin supplement
4) Flax seed Oil
In my case it really worked. I've also suggested it to about 5 other friends who have faced hair loss issues and it helped significantly. Also, don't wait a long time. It's really important to turn it around as soon as possible!