Introduction: Hi I am rick, and I am 14 years old. Somethimes I have really weird dreams, and I hope you guys know the answer to them.
1st:
I had been on a vacation. When I was home, I discovered there were 2 exotic animals I took home with me. 1 yellow snake, and one very, very small spider. They were in my room, and I was looking for them. I eventually found the yellow snake, and it tried to attack me. Without succes. The poisenes spider however, was nowhere to be found. This really scared me...

2d dream:
I was in a city. There was a taxi I took. It was really strange, cause I did not tell him where I wanted to go, and yet he said: I know a shortcut, we will take that road. So I simply agreed with him. Suddenly we were in the middle of nowhere, and he said: Step out of the car. So I stepped out. Then he said: I made a horrible mistake, I have to go now. He was away very quickly. I was all alone. There was a factory in front of me. A very old one. It stopped working. Suddenly, there came smoke out of the factory. Black, thick smoke. the air was very poluted...and again, yellow(just like the snake). Around me there was a forrest. Suddenly I just knew it was year 1900. There were people working there again, very poor people. I felt really scared.

Hi Rick; you could start by looking up the symbols, snakes, spiders, yellow etc in the Dictionary by clicking the button above, and the Dream Themes page which has a page on color and see if anything on the Archetypes page fits too. It's really all about what some of the things mean to you; do you like spiders or hate them, what do snakes make you feel like and so on?

I agree with Maljonic that a lot of it depends on how you personally feel about the things in your dreams. I think that the snake attacking with you might mean that something is bothering you, and the fact that you can't find the spider could mean that you are having trouble finding out what is wrong or what you have to do about it.

The second dream about the taxi also brings to mind the theme of being lost. In the first dream, you've lost the spider, in the second you are lost, in space as well as in time.
Maybe the feeling of being in the 1900's specifically came from a book you read or a film you saw, maybe even something you read or saw a long time ago.