Ok well ive been doing that all day its been like this all day since 930 this morning
Maybe take the battery out and leave it for a minute. When you turn it on have you pressed it down for more than 15 seconds? If none of this works, try a new battery. And if that doesn't work then you will have to take it to the store you bought it from and see if they can fix it, but most likely they will say that you will need a new phone.