Tenant from hell.

I’m a new live in landlord who rented out the spare room for the first time as I needed the money to help pay for the mortage. My tenant paid his deposit (provided reciept) but didnt sign a contract. We had verbal agreement that we’d give a month notice if he was to ever move out. After a few weeks of living with this chap things started getting weird. He started stalking me, going though my post, emails, alienate my friends, the final straw was threatening my girl friend in a sick email as he was convinced he was in a relationship with me. I gave him a months notice. He moved out the following day leaving me in the shit. I told him he didnt keep to the arrangement of 1 months notice and due to the lack or respect, behaviour, harrasment and making me feel uncomfortable in my own home he will not be getting his deposit back. He is now turned it all around saying I forced him to move out etc and taking me to the small claims court for his deposit. Please help as I am worried and not sure where I stand on this.