Can you talk to your landlord about the situation? Tell the landlord everything that is going on right now. They aren't all heartless people (I own some rentals myself).

S/he may give you the option to sublease the apartment or at least let you out of the lease when she has a replacement. I am sure your landlord doesn't want to be in a situation where one of her tenants isn't getting the rent in on time or at all. It would open a huge can of worms for her.

Read your lease very carefully and see what it says. You also want to think about if you just want to leave. If your credit is good right now its probably not a good idea, but if it isn't so great, you don't have much to lose. Most likely your landlord wouldn't report this to the credit agencys anyway unless the landlord is a big company. I have had it happen to me and I haven't reported it.