2006 Ford Focus making loud sound in rear?

My 2006 Ford Focus has 30,000 miles on it, and a few weeks ago it started making a loud sound that sounds like it's coming from the right rear portion of the car. It seems to get louder as I accelerate, but it's kind of a constant hum while I'm driving. Someone mentioned wheel bearings to me today, but would that be a problem after only 30,000 miles? I really need my car until I get the money to have it fixed, but obviously I am not going to put my life or anyone else's life in jeopardy if it could cause an accident. I'd appreciate opinions. Thank you!