A friend (no longer) and I decided we would rent a room together for the summer (2 months). In the middle of the second month she told me she was going back home and since she was leaving she was only going to pay for half the rent of the second month. She told me I had to pay the rest since I was going to have the room to myself. She gave me a sob story of why she had to go home. At first I agreed but then decide it wasn't right and told her she still had to pay for the full month since that was the original agreement. I was a working student barely making enough but some mutual friends believe I acted unfairly since she was going through something. So AITA? 