If you’ve spent your whole life in a smaller space and have just moved into a house with multiple rooms, I think it’s normal to feel a bit uncomfortable as you adjust to any new living situation. However, if you are feeling overwhelmed by fear, or feel it is negatively impacting your life, you should speak with a professional counselor. A professional counselor/therapist may be able to give you some helpful tips for dealing with your fear, or can help you figure out if there are deeper issues that need to be addressed (the situation may not be about the physical space – there may be other experiences in your past that are making you feel this way). If you are 18, are you still in high school? If so, is this something you could address by talking with a counselor at school? that is usually a good free way to get some professional guidance.