Im Really Scared of my dog?

whenever i go outside to do chores my dog follows me and im fine but whenever we get far enugh away from the house when he knows i cant run back he attacks me this happened 2 times nw but the second time i came prepared i brought a belt half the size of a bowling ball truck and a long sword like wood i was getting the trash and right when i was far enugh he attacked me so i threw the truck as hard as i can it hit his head but it did nothiong he just still kept going and then hes usually afraid of the belt and he was until that time and i started whacking him then i finally just ran back hitting him along the way and im really scared im only 13 the 1st time i tackled him but he is really strong and i ended up on a slide for 20 minutes so what shuld i do