Do I stay or do I leave?

[Amanda]

I am an editor at a publishing company. A lot of the time I find myself without much to do at work. I am often bored. I often find myself making up work to do, just to keep from sitting, staring at my computer.

My officemate has about an equal amount of work to do... but doesn't do it. She will put things off until well after the last minute, and sit there and IM people and stalk Facebook. My officemate and I were hired to do the same job. They couldn't decide between the two of us, so they hired us both. It is obvious to me that each of us could easily handle the other's workloads in addition to our own.

I've considered leaving. I've started applying to jobs elsewhere. I fear that when I do find another job, and have to tell my boss that I'm leaving, that he's going to ask why, and I'm going to say, "Because I'm bored?" "Because you didn't need to hire two editors?"

The hard part is that I do love my job and my co-workers.

Any advice or thoughts would be appreciated.