Confusion

So im a bit frusterated with this work deal. I got my shift covered and everything, went to Disneyland thinking my shift was covered... but no. Of course I get a voicemail saying that no one showed up, so its my fault. : Apparently when I said "next weekend" that means "2 weekends" because thats what I told the girl who was going to cover for me. So now my boss is a little frusterated, as am I, because no one was there on Saturday. Oops.