I Found An Earthworm Swimming Around In My Toilet Bowl

I found an earthworm swimming around in my toilet bowl tonight. It is reddish brown in color. I took it out to take a good look. It really does look like an earthworm. I live in the state of Washington. We have had rain and snow. I am also on a septic tank. What do you think? I pray it is not from me. Are there worms that live in the body that would look like an earthworm?