Don't take the gauze out whatever you do.The gauze right next to where the extraction was is trying to help a clot form,if you bit on it slightly or press on it,that's just like when you are told with a wound to apply pressure.
Don't use any salt washed until it has defiantly stopped bleeding tomorrow,your dentist should of told you this.
I know it can seem scary when the bleeding goes on and on,but keep the first piece of gauze where it is and eventually it will stop.
Good luck
Aya