help please

 please help me!
my friend and i are being followed by this.....thing.....all we know about it is it's an evil, negative, spirit and it wants us and everyone on this planet dead.  we're trying to fight, but idk if it's working very well.  if you can't help me with that, could anyone please give me some charms or tips to keep away evil, negative, spirits she can use?  i'm not too worried about myself, but i want to protect her with everything i've got, which isn't much right now.  i need help with either one of these.  please message me back if you can.