Anyone have really bad pp hair loss?

I've read and read about little whisks at the front hairline, and I do have those, but I also have crazy bad hair loss on the crown of my head. I used to be able to have a nice smooth pony tail and now it's all lumpy and parts funny because their isn't enough hair to pull back into the pony. If I leave a pony tail in for too long it will part and then you can see my scalp. It's not necessarily a bald spots but it is sooooo thin that you can see scalp.

It sucks. Please tell me my hair will grow back.