I am the only name on my apartment lease in London Ontario…

I am the only name on my apartment lease in London Ontario Canada. I decided to get a roommate to help with bills. I found Ann Marie on Kijiji and she said she was a sheriff from PEI. She seemed like a nice person so I agreed that she could move in. She said she could pay first and last. A week before she moved in she told me she was in a car accident and had a big unexpected vet bill for her dog and as a result would be short on funds upon move in. I tried to accommodate her by saying she could pay me last months rent over three months: instead of giving me $1200 on Sept 1 she could give me $550 on Sept 1( $600 minus a $50 deposit) an extra $200 a month over the next three months. Ann Marie agreed. She barely moved in, brought a few bags of clothes but no bed or blankets or pillows or furniture. She slept on the couch and the floor in her room for about 1 week and a half. I had been gone from the apartment for about a week when she texted me in the middle of the night saying she had moved out and cited a variety of reasons, mainly that I smoke week and my dog stressed her out. When I pressed if she was going to pay last months rent still she cited a variety of changing reasons which culminated in a personal attack, telling me that I had mislead myself and my lifestyle and that is was toxic to her mental health and therefore she doesn’t owe me money. I was very upfront about my lifestyle and the fact that I live with schizoaffective disorder and sometimes act strangely, particularly at night when I take meds.
My question is, what are my options for getting last months rent? Or is she right about being able to leave a lease because you deem it bad for your mental health? We didn’t have a formal rental agreement but I have text messages that confirm and prove she was adequately warned about my lifestyle before she moved in. i have access to free legal services thanks to school. If I take this to small claims court, do I have a case? Thanks