Used condom came out of empty milk packet in the bin

Last week a cat entered our flat. It kicked our trash can open and spilt the garbage. It was a mess with all the trash lying around.

As I was trying to pick it up, there was a milk packet lying on the floor. When I picked it up, something fell from it. It was a used yellow colored condom. Some fluid was flowing from it. I was so disgusted.

To give some context, I live in a rented flat sharing with my elder sister. She must have hidden the condom in the milk packet so it is not visible. But the cat made a mess of it.