Could I Be Encountering Spirits?

I have never been the kind of person who believes in mediums or anything of that nature but reason events in my life are beginning to make me change my thoughts. Recently my roommates and I have been experiencing some odd things. First, we all have often felt like we are not alone and being watched in our room. Second, when I'm in the bathroom I constantly have a fear of looking in the mirror because I swear someone will appear behind me and while I'm showering I feel as if someone is right outside the curtain. Also, I've always been the type of person to sleep through the night and ever since I've moved in I have woken up in the middle of the night and seen an image of a man somewhere in our room. One of my other roommates admited that she had also seen the same man in her sleep but she had actually talked to him. The other night I actually experienced multiple people in our room but I keep assuming it's just my imagination. Last night I had a dream which I was not a part of and in it the girl had brutally died, I woke up immediately and could swear I pictured the same girl in the middle of the room and within a few seconds a light flashed and she disappeared before I could make any observations. The flash was kind of like that of a camera but instead of flashing throughout the room in appeared quickly and folded into itself. The people that I have been seeing in my room are not exactly people. For example, it is not as if I feel like a stranger is just standing it my room it's more of blurry images that appear in front of me and then develop in my head and disappear very quickly. The images only happen at night so I'm not sure if it's just the dark playing tricks on me or something more. I never really feel scared of the images just more unsettled and confused. The past few days I have just felt like someone is constantly with me. My sister has a past of odd experiences as well. When she was very young she would tell us that night people visited her and told her things. For example, at 2 years old she told my grandmother that her night people had told her she was going to die and unexpectedly two weeks later my grandmother died from undiagnosed melanoma. She used to tell us that she had good night people and bad night people and she often hysterically woke me up at night if only the "bad night people" had visited her and not the good ones. I haven't thought about this in years but the recent events have reminded me of it. Again, I have never been a nervous person about this type of thing but lately I have just felt extremely anxious at home. Am I just being paranoid or could this mean something? Any answers would be extremely helpful.