"Greasy hair"?

Asked: "Greasy hair"?

(Before I start off, yes I am a girl.. the "Mr" was a mistake..)

Anyways, few weeks ago I started straigtneing my hair I left it straighten without washing it, and everyday I would straightnen again, even though yesterday my hair was straighten, and then after my week is over I would wash it..

My hair is starting to thin out, it's so think I am starting to feel my skalp, I use to have very strong thick hair, and my hair would always grow so much always to but my butt very fast, I would always need hair cuts underneath my neck, pretty well short hair, not hair that's at my neck, where my breast is… Akward to say that, anyways, I would get it cut there…

My hair is starting to thin out all the sudden? Ever since I been straightneing and I believe using Head & Shoulders shampoo because I do get dandruff, and even after a wash and rinsing my hair even running threw my fingers threw my hair, my hands feel greasy.. And soft from running through it? And when I have my hair in a pony tail, my top of my foward is a little empty because my hair line is so pulled back from always putting my hair in a ponytail everyday! And from the sides, you can kinda see my skalp, my sister who is a hairdresser a year ago caught that I was "balding" this is because of pulling my hair back, not because of medical issues, It's because all my life I put my hair in a pony tail, just this year I started straigtneing and then is when the 'Straightneing issue' began, I don't use heat protector….

Is there anyway to grow my hair back, healthy, without it greasy? And are these Shampoos any good? Head & Shoulders, Bedhead, Olive Oil..etc ? I just want my hair back, It's so thin, even my pony tail is so fin, it use to be so thick, my hair was naturally straight, but the straightner made it look even better, but now it starts to go curly even after washing..

What do you guys recommend? Should I stop straightnening, should I use head protector..etc

Thanks..