I accepted a job out of desperation 4 months ago and now I hate it?

I don't know what to do. I took a job that was through a placement agency (it's a regular job - not a temp job, meaning the actual company pays me). I was told if I left within a year I'd have to pay back the $4000 fee the company paid the placement agency to find me. Well it's been 4 months and I'm miserable. I was out of work for 4 months and desperate for income so I took the job (under the impression it would be a higher level job). It's not higher level. It's really low level. I'm bored to death. I did not sign ANYTHING saying I agreed to pay back $4000 if I left. Do you think if I find another job in the meantime I'd be held to that? I was only told verbally by the placement agency and the actual company I work for said NOTHING.