I have had a similar experience with dreams, when I was younger my dad worked as a bio-teacher at a college, and as part of his work, he was allowed to play around with some of the local animals that the school had. I would often go with him to his work, so at one point in my life I was perfectly fine with spiders and snakes, as my dad would let me hold the snake, and look at the spiders. (The snake was a python or a boa, I can't remember which as I was like 4.) but one night I had a dream, in this dream I was all alone on the streets of New York, and the sky was pitch black. I felt a rumbling under my feet, and for the next few hours, I was chased through New York by a GIGANTIC tarantula. it all ended when I jumped on a raft on the beach, and right when I was out of harms way, a snake came out of the water and began to strangle me. At which point I woke up. Since then I have had a very strong fear of snakes and spiders. Although I am a little embarrassed to admit it, my girlfriend has to kill the spiders for me...