My hair is thinning like crazy !?

ever since i got my asian mullet my hair has been thinning liike crazy ! i see that little white part of my hair along with some of my hair that falls out. i dont tie my have up but i do clip it up. i dont use gatsby, mousse, hairspray, and heat appliances often so i dont know. my mom said something about me loosing too much blood during my period and that my iron level is low. but im not sure. my hair used to be so thick and if i tied it in a ponytail it was super thick that i could only tie it around twice. someone please help me and give me advice !