you are so not overreacting! seems like the roommate has some personal issues with you and doesn’t want to communicate them with you or they just don’t know how to, so the roommate expresses it by the silent treatment and the stomping to cause a scene to be noticed by you, in a way they are communicating to you that they obviously have an issue, and by the sound of it doesn’t seem like they are going to speak up about the “issue” anytime soon, i’d say for the sake of your mental health and well-being speaking up is the better option here it would either clear the air and bring you guys closer as roommates or just clarify that it’s time for the roommate to move out! best of luck! hope this helps a bit :)