I died of a stroke or heart attack (I'm only 18)

The dream took place in my high school. In the beginning, I look into a restroom mirror and place my hand on my heart. The abnormal heartbeat I feel indicates that I will die soon from a stroke or a heart attack (whichever causes sudden, immediate and in my case un-painful death). Strangely, I indifferently acknowledge this and exit the restroom. While walking past a few students in the hallway with my eyes averted from theirs and with my head down at times (how I usually walk in public places), I suddenly feel/hear an inner "boom", which represents the death of my heart, or maybe nothing at all (I don't remember) and then collapse. While falling to the ground, everything is in very slow motion. It's like I'm being pulled unusually and heavily down by gravity and i'm trying to resist but the force is too strong and my body is already no longer of my control. The hallway is empty of people but there is a classroom just behind me and I can see it because my body is falling face up, facing the direction I had come from. I can just make out some heads of students through the upper glass part of the door but, paying attention to their teacher, they don't notice me back. The detachment I feel from the physical world and especially from my body is overwhelmingly surreal and unnerving. The thoughts that run through my still functioning brain (I guess my brain hasn't died yet) are:
-I don't want to die here in school, where all the students will find me. I wish I could've died where only my family could found me.
-I wish I could at least adjust my bra because my chest may be visible through my shirt. I can't believe I can't move my hands or any body part. I don't want to be found so physically awkward like this.
-How come I can still think and feel? When will my brain die, in a couple seconds? Or is there such thing as a spiritual world and am I in it now? Will I stay like this forever, without a body and invisible to people? I wouldn't be able to stand it..

The entire dream was silent, without any talking or other sound really besides that "boom" I felt within me. This is only the second dream I've had in which I died. I was shot in the first one but I think it was caused by a gun film I had watched before sleeping. I had an emotional experience similar to the one I had in this heart attack dream last year when I thought I was going to die from a traumatic prescription overdose that caused my heart to beat rapidly (i had minor depression). The overdose is a whole other story but the main point of it is that I don't think it was much of a suicidal act. Extra info about me: I will graduate next month and go to college in the fall. I do often feel emotional detachment not really from myself but from others, especially when I'm in a group or in a public setting (I get amused by the emotional unity of a group of people in reaction to something and observe their facial expressions. and I don't feel the same emotion as they do). I think about death sometimes to often and usually of loved ones rather than of myself.