Why is it when i touch bugs i feel sick or disgusted?

a millipede or centipede looking bug just crawled across my kitchen floor so i grabbed some paper towel and grabbed it but when i felt it squirm between my fingers i got a quick sick feeling or really disgusted reaction as if i didn't like touching this creature or something retarded like that and it dropped but the second time i just forced myself to grab it and run and throw it out the front door instead of my first thought the toilet