I was away for a week and my roommate had a friend over. I came back and there were some crumbs on the floor of my room so I asked her if her or her friend were in there and she told me she slept on top of my bed (with her blanket and pillow) because her friend took over her bed. We have a fairly big couch which can be slept on. My roomate just finished medication for C diff. Which is quite contagious and can last on surface (including her clothes pillows blankets etc) for up to 5 months according to some sources. My bedroom does not have a lock on the door as it is a student place so i could not have locked it prior to leaving. She is my friend and I don't want to start a fight over this hut I also am quite upset. AITAH for being upset and expecting reasonable privacy for my bed to not be slept on while im away. Or at least expecting to be asked before that happens. Additionally she didnt tell me until I brought something about it up which i think makes it worse. I havent confronted her about it I kinda just laughed it off in the moment but am now realizing how mich it is bothering me. What should I do?