Creepy Things Are Happening Want Explanation

Hope you guys are having a good time, I am not a psychic or anything I just, I need your help, I am experiencing something scary, need your help. I am a really quiet and reserved person but I can tell by just looking at a person and especially by their voice, the way they talk, I can tell about a person by that, I don't know if I have some gift or anything but I can somehow get a glimpse of future, I can get an idea what is going to happen and I can tell about a person without talking to them, sometime at night I can hear unsettling voices, screams but that's not why I need your help I need in explaining this phenomena. Many times when I am out of my house I can see people who look normal but when I look them closely they start talking to themselves in a creepy manner by just looking down and talking to themselves and smiling weirdly. No one else around me seems to notice it. They don't look any different, they look the same but they are different, most of the times they appear on corners of streets or on the back seat of bus they just look towards ground, talk to themselves and smile. It all started 2-3 years ago, whenever I am alone I feel like people are watching me and they are judging me, sometimes these voices makes me feel weak and because all of that I am suffering from anxiety and depression. Please tell anyone what is going on you guys are more knowledgeable. Can anyone explain what is going on? If they are normal? How come I see them on daily basis? Please tell me if anyone can understand.