Is there anyway to get out of this tenancy agreement?

123mcg

Me and my boyfriend have just moved into a new flat. We first saw the place about five days ago. We wasn't too impressed but the landlord said that he would do the place up, i.e paint it and clean the place up. We signed the tenancy agreement before we got the keys, because the landlord ask us to. I know now that we should of waited but we put trust into him. We got the keys yesterday, when we went the place was dirty, they hadn't painted some walls, there was lots of rubbish outside and we had no idea how to work the electric storage heating, or even if they worked (when asked prior to moving in he said they did work). We tried to clean the place up but there dripped paint everywhere and the place is a dump. We went again today optimistic that we could attempt to make the place a home when we discovered fresh rat poo on the floors. The carpet had been chewed and there where holes in the walls. In the kitchen there is also evidence of rats, however we haven't even had any food there yet; we don't have any of our things.
Im five months pregnant and there's no way i want to live there. Im at the point where i want nothing to do with this landlord, and i just want to go back to my parents home! I undestand that we may be stuck with this property but i would even prefer it if he could place us somewhere eles.
We really want to get out of the contract. Its a 12 month contract, and the when my boyfriend's mum asked the landlord prior to moving in if we could ever move out he said that we 'cant'. But ive heard about a two week period in which you can move out, or if there is anything we can do?
Thank you for taking the time to read this