methamphetamines and hair lose?

I was heavily using methamphetamines for three months. Right when I quit I started losing a lot of hair. I used to have very thick hair. Now it is pretty thin. I know it is normal to lose hair when you brush you're hair but when I brush it falls out like crazy. I was brushing my hair the older day and two handful came out and one of my brushes was full of hair that just fell out. If i just run my hand through my hair gently the hair will fall out. I've been clean since September. Shouldn't it have stopped falling out so easily by now?

: http://alcoholdrugstreatment.info/methamphetamines-and-hair-lose