I think my cat wants to kill me?

I have adopted a cat from my friend few week ago. At first he was normal and seemed a bit shocked by the change of house and everything, but the last few nights he has been scaring the *hit out of me, firstly he keeps sitting on the corner of my bed just staring at me, one night I kept one eye open and watched him for 10 minutes and he wouldn't stop staring at me and when I wake up in the morning he is really close to my face, the next night I pushed him off my bed and he hissed loudly and bit me really hard and just jumped back on the bed, after that he turned very aggressive. When ever I come home from work he hisses really loudly and runs towards me. So I have to come home through the back door. When ever I put food out for him I have to be out of the house otherwise he runs towards me and starts biting and scratching me. I've tried locking the door when i go to bed but the door is suddenly covered in scratch marks and my sofa and over things are torn to pieces and one time he came towards me so I quickly picked him up and held him in the air and prevented him from getting me but he just start to go crazy and started to viciously shake, meow and hiss really loudly and continuously kept trying to gnaw at my face whilst biting the crap out of my hands... I'm worried, I have to climb through my window to get to work. That's how bad it is, what should I do?