Should I have to pay rent for the remainder of my lease?

I have moved out of a shared house. I left at the end of September and my lease is not up until January.

I left for several reasons...

1. When I moved into the house I thought the maximum number of people living there would be 5, including me (there are five bedrooms, it is a large house)
- I did not know at the time that one roommate had a son that lived with her on weekends
- Half way through my lease my landlady moved someone into our unfinished basement (which brought the house total to as many as 7 at a time)

2. The roommates that lived there were disgusting
-They would trash the house and not clean up after themselves even when told to
-It became so bad that I couldn't even use the kitchen or store food in the fridge

3. The roommates would steal things like food, detergent, etc. even after they had been asked to stop

4. The landlady refused to spray the house for bugs adequetly

5. The neighborhood was unsafe, a roommate had been shot at when someone attempted to steal his car

6. A roommate physically assulted me and she refused to remove him from the house

My landlady is now emailing me threatening to sue me for the remainder of my lease. Should I have to pay her?