Why do I have a bald spot on my head? ?

Hi everyone i'm a 12 year old girl who straightens her hair a lot ! & today when I woke up my sister noticed a bald spot on the left of my head ! i'm thinking I got the bald spot because of so much heat damage on my hair ? please help!! i'm getting really scared!! will more of my hair fall off too ? ooh please help! thanks =)