Sparklefizz I know exactly how you feel. I have a purely visceral response to the sight of a spider. My muscles jerk, my heart races and I feel nauseated. I have actually thought I might be sick when catching sight of a really big spider. I hate the beginning of autumn for obvious reasons. If there was something that definitely deterred the beasts, I would use it.
"Grow up, they're harmless, they're more afraid of you, they kill flies, blah de blah..." Makes no difference when people say these things, because it's a primitive fear that bypasses the rational mind. You go immediately into fight or flight - in my case, it is flight, whilst calling for my husband to rush in and remove it. I can't imagine how I will cope if I ever have to live alone. Getting therapy is possible but I am not convinced it would work and I don't know if I dare to do it, to be honest.
Who knows why some of us fear them? I didn't get it from my family. Mum was scared of rodents and moths, my sister was scared of worms. Maybe arachnophobia is related to the speed, the scuttle, the number of legs... or maybe it's the ancient fear of something dangerous. Our ancestors must have encountered venomous spiders, and maybe they passed the fear down to us. Or maybe it is an inexplicable phobia like the fear of the number three or of choking on peanut butter. Whatever it is, it isn't easy to get over it.