An Irrational Fear

I can't recall when I became so terrified of bugs. There was no specific instance I can point to as an explanation for my fear, I only know that I didn't used to have a problem with them and now I do. Not too long ago a friend and I were discussing our irrational fear of all bugs. As we both talked I began to realize how completely insane we sounded. This didn't help allay my fears, it just made me realize how crazy those fears were. I have to check inside my coffee cup each morning in case a spider got into it (because I once saw a spider in one of the coffee cups)and my shoes in case a cockroach crawled in. At night I won't walk around downstairs without slippers or shoes on my feet (a habit I developed recently after seeing a cockroach in the family room). I also will sleep with my entire body under the covers, including head, if I hear a fly or mosquito in my room (so they don't fly into my ears, nose, or mouth).
Any kind of bug bothers me to a certain degree, though spiders and cockroaches are the worst. I can't bring myself to get anywhere near a cockroach. It took me nearly five minutes of standing outside in the dark last night when I saw a cockroach in front of my door before I figured out a plan to get in and worked up the nerve to implement it (the plan being - stay as far from cockroach as possible while trying to scare it away with stomping and/or my shadow). And, of course, when I finally scared it away and ran inside the house a cockroach was waiting inside as well. I made some sort of screeching sound out of fear and fled the room, grateful I didn't need to linger in there to turn out the lights since my brother still wasn't home.