Dear Curious,
I . . . had a similar situation with my uterus -- mine was uterus didelphys, which means I had two separate chambers, two cervixes, and two vaginas. That's all gone now as I had a hysterectomy a year and a half ago. Bicornuate uterus usually means something similar but not quite as completely divided, but sometimes doctors use the bicornuate term somewhat generically to describe any similar anomaly (abnormality) of the uterus.
This kind of anomaly is called a Mullerian Anomaly and is rather rare, but not as unusual as once thought. With the advent of fertility doctors and advanced imaging techniques, more women now know when there is a strange twist or turn of the uterus.
There are mullerian support boards on the internet, I know that there is a yahoo group for this. Those women know a lot about the condition.
Your uterus being enlarged may mean that you have fibroids, which is annoying but not the worst thing.
I hope you've gotten a lot more info by now, but let me know if you have any more questions that I can help you with.
BTW, NOT all gynecologists are experienced in dealing with our unique health needs, so please find out if your doc has a clue what she is talking about. If she tells you it's no big deal and you're really just like everyone else, please seek another opinion.