Nausea is the atmosphere in your dream. You want to "get rid of", but your feet hold down the bugs, and those narrow spaces hold down the bugs. You want to clean up those dirty spaces.
Especially when you are desperately trying to get rid of something, panic will make you do things that hurt yourself. The worm you tore represents some kind of inner power, some kind of power that cannot be eradicated.
I think earthworms symbolize what scares me, and the space of feet represents dirty or private space. Together, the two are your contradictory emotions. Something intrudes into your space, and you don't want it to enter, but you can't definitely refuse it.