Dream about a snake biting me?

I had this dream where I was a backyard by a fence and I was looking out to a field. I suddenly felt fear that a snake would make an appearance. I also had a dog by me. Well, I walk into the front yard and I get to this fence door and I suddenly see a snake coiling around in the grass. I tell my dog to get back and the snake thrusts itself at me and I get ahold of it. I thought I had it's head securly but it bit my arm. So after that I like...snapped it and ran away into the house. What could this dream mean?