Confused On What I Feel

Ever since I was a young girl I have been able to see things at a glance that nobody else has. After I see them and turn back there gone! Could this really be people or am I thinking I see something but there really never there? It's always been scary but as iv got older I have got use to it. More normal I guess you can say. As iv got older its been I will get this feeling something bad has happen or is going to. Sometimes I will have dreams about it. Or I will hear someone say things or my name and nobody even around or speaking. If someone could please explain this to me. I would greatly be thankful! I had a feeling that something had happen and when I get the feeling that it has I will get very depressed, mad and upset. Or sometimes I get a happy feeling. It's very confusing to me! And I don't want to tell people just because I don't want someone to think I'm crazy or just saying things. Also in my dreams if something is going on I can feel the pain or anything that is going on in the dream. I can always fill a vibe with people or places, its like I get a gut feeling! If I have a gift I really want to get more information and learn to take it into more. But my main question is what is going with me. I had a feeling one day after my great grandmother had left my house and for rest of that day until the next day I just felt so down, and upset an I didn't know why. I had a feeling something bad had happened and come to find out she was in a wreck! Alot lately I get bad feelings and so upset and I have no idea why.