Writing and Stealing

I've started writing a story. I find myself thinking of that silly segment on Letterman "Is this anything?", where they have someone on the stage doing something ridiculous (remember the big bald guy who could spin the smaller guy on his head?), and Dave and Paul decide if it is "something".   I haven't decided if this is "anything" yet. 
I find myself stealing things. Like names. Not on purpose, but it happens. For example, my hero's name was Matt Pomfrey. To which James immediately pointed out, "Oh you mean Madame Pomfrey, from Harry Potter?" Oops.  I was going to name a character Jacob. That's a common name, right? Well I can't do that because everyone will assume he is a werewolf. My main character's name is Emily Morris (changed from Emily Morgan, who I remembered is  friend of mine from high school). Her nickname is Mo, a name that my sister bestowed upon me a few years ago. That's all well and good...except she is a teacher. My cousin is a teacher. Her maiden name was Mouritsen. What did her students call her? Miss Mo. Oops, again.
I've also noticed that how well I write depends a great deal upon how I feel. If I don't feel well, I don't write well. The last couple of days I have been ill, and I haven't been able to go anywhere with my story. The ideas are cliched and stalled, and the words are cheap and childish. I'm not trying to write the next Crime and Punishment or anything, but it would be nice if it didn't suck.