You’re in a really big situation. It’s almost the same as Nezuko’s situation where she tries to refuse Sanemi’s blood to prove that she won’t kill anyone. You were trying to refuse Sanemi’s blood because you just became a demon while doing your mission. You proved every hashira that you won’t kill anyone. And then, Rengoku stepped in and decided on taking care of you while you still fight demons even though you became one. Rengoku was also your Sensei so you trusted him a lot “Long day, eh?”