Feeling let down by a friend?

Hey guys sorry for the post but not sure were to turn. So me and my best friend work together ( i always take him home from work, no biggie its only 15 Min's out of my way) but what i am mad about is he asked me if i wanted to do something thursday i said yes ( canceled other plans) and he makes other plans after i cancel what i was gonna do. When i try and talk to him about it he yells at me. What should i do? I don't wanna lose this friend but this is not the 1st time, and i don't feel very respected.