Why was this dxm trip so horrible and vivid?

I had a very traumatic trip one time in high school when I was still abusing cough medicine, and I'm wondering why this played out as it did. I came home late in the evening to my parents house very tired but decided to trip on cough medicine for fun. I took 2 bottles of robitussin, however because was so tired I promptly fell asleep after taking it. I must say that I was downstairs in my bed when I fell asleep for you to understand why what happened next was so odd.As I "woke up" or came into consciousness or something I was WALKING upstairs in my house and I had no control over my motor skills at all. My feet were walking but I was not controlling them. I was extremely spaced out and freaking out of my mind thinking I was going to be insane for the rest of my life and that my house was, in fact, hell where I would spend all eternity. I looked at the clock after what felt like hours and it hadn't been even one minute (yes this was very vivid and frightening so I remember every detail) If I tried to talk it sounded like the flanger effect on a guitar. I also had tunnel vision. So I ended up downstairs and I felt like I was walking on a track made by fate or something and when I reached this certain point that I was headed towards I would die. As I was walking around I tried to make myself stop but I couldn't, because I was not control of my feet. Then as this sense of impending doom continued to grow I reached this "certain point" in my room and stood their and my vision went black. I saw a small orb of blue light in the middle of this vast empty black space and then I was encapsulated in it and I felt that I had died, and it was over. Then as I looked around me, the the orb turned red and I felt that I was reborn and I "regained consciousness?" of my basement. This whole orb ordeal only felt like a minute each time and I continued to walk around my basement coming back to that spot to die and be reborn and I remember the feeling of dying and being reborn as the most horrible feeling I've ever had in my life. One of total chaos and fear. Anyway I'm sure there was more but I don't remember anymore of it luckily. I'm just wondering if anyone can interpret or figure out why I would had such a wierd and traumatic trip.