I'm REALLY scared of spiders..

If I see a spider, I'll literally freak out, and I won't go in the area it's in. If a spider is in my room, I have to get someone to kill it or I won't sleep in my room. Even if it's one of those small spiders, I'll freak out. I don't understand why I'm so scared of spiders if they're so harmless! A couple of days ago, there was a spider on the desk that my computer is on, and I haven't touched my computer since (I'm on my iPad) My fear for wasps and bees aren't even as bad as it is for spiders. How come I'm so scared of spiders!?

This is a mental conditioning, much like brainwashing yourself into fearing spiders.
Rather than go through the long repetitive process,here, you might read my response to similar question here:
http://answers.yahoo.com/question/index;…

because you just can't get over the idea of being scared of spiders

Because they're bad ***

You will have to train yourself to get used to them. It is fine being scared of dangerous spiders but freaking out with harmless species that are not bothering you is another matter. Wherever you are at the moment there is a spider within two metres of you, probably more than one. If you are outdoors, there are dozens in every square metre. Most are tiny and you are not aware they are there.

I am scared of spiders and the thought of a big one running over me is the stuff of nightmares but I have to live with the things. I tolerate the small ones and have learned to remove large ones like huntsman spiders. I still don't like them but I can even go to sleep now knowing there is a huntsman in my bedroom. You'll get used to them.