Sudden Feeling

Good day everyone. I am new to this site so please be patient with me. Well have always had moments in which I can predict things. But there was one time and it was the first time it happened to me. I was in school and I was have a good day. I felt great, no problems at all. Then I went to my history class which was period 7 and then suddenly I felt horrible. I started to feel really bad pains in my chest and then I got up and went to the rest room where I started throwing up blood. NO JOKE. And all I thought about was someone very special to me. The love of my life. Once I was able to leave the bathroom, I started walking toward my classroom and there was a cop standing out the classroom talking to my teacher. I looked over at the police officer and I felt my heart get heavy. He looked at me and said " I need you to come with me ". I automatically knew it had to do with the love of my life. While I was walking with him I suddenly asked the cop " he was shot wasn't he?" the cop looked at me and said "how did you know?" and I told him " I feel a heavy heart, I have chest pains, and I'm throwing up blood, and I picture AB shot and in a pool of blood!" This was one of the worst experience ever. AB had been shot and I was taken to the hospital to see him! I couldn't look at him because I felt like I was going to die. But I had a feeling of relief when I saw him which now I interpret as that relief being that my spirits were telling me that AB was going to live. And it has been 2 1/2 years since the incident happened. Now I suffer from anxiety when something is about to happen. Please help me understand why this happens. Thank you