I think im insane.. i've been getting this feeling that im going to die soon.. help!?

It sounds like anxiety to me. The mind does surprising things. Sometimes an anxious person will become a hypochondriac, imagining illnesses. Why? It's not rational. Well, excessive anxiety leads to irrational thoughts. By definition, there is no logical explanation. Also, you might be saying to yourself, "I shouldn't be thinking about death" and then that makes you think about it more often. Anxiety takes many forms. It can be treated, whether it's constantly there or just comes around now and then. Don't try to make sense of it, because it's not related to intelligence, or to knowing or not knowing what is true. I'm glad you enjoy being with your friends... but it sounds like sometimes your stress gets to be too much. Your famioly doctor can probably help you... it's not always necessary to see a psychiatrist.