Explain this experience please?

something wierd happened to me the other day i was sleeping and i started to hear this song playing in my head like i was listening to it on my ipod. the song was jeff buckleys hallelujah. then tears started to form in my eyes and i seen my grandparents who have both ped away standing in front of me clear as day. When i opened my eyes a bright light blinded me for a second and in my window i could see a figure of a person then my eyes shut again and my body began to shake and i forced my eyes open and i seen a dark figure standing next to me through my peripheral this figure made me anxious and my body started to shake again and my eyes closed. i forced my eyes open and i was completely awake. this freaked me out and i cant explain it im a 18 yr old college student please help me. it all felt like it happen while i was half asleep and half awake.