What actually caused it?

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I was awake at 1:00 a.m and then again at 2:35 a.m today...Till 4:54 a.m I didn't get a wink of sleep though my eyelids were heavy. I drank water, used the washroom, the AC failed to lull me to sleep so took a tour of our dining room, and returned to bed. As I was unable to sleep, I listened to some music and watched some videos. I was sleepless throughout midnight almost. Around 4:54 a.m in the morning, I slept and when I woke up the clock showed 5:30 a.m. merely half an hour. I got a dream where I saw my late mother dressed exquisitely with gold rimmed spectacles in a crowded bus, standing, my sister standing just next to her. I was seeing her, eyeing her, because I could not take my eyes off her, from near the door. I had not boarded the bus. Meanwhile the scene changes. I see a sick girl, take her in my arms and lay her down somewhere attending to her while I let a boy play with a ball. The girl lay unconscious. Presently my mother comes up to where I was, a huge empty room with a bowl of what looked like very little potato curry...My sister too came, meaning they didn't leave and again the scene changes to that crowded bus, my sister sitting in an inclined position smiling and my mother sitting opposite her, laughing and bending her head touching my sister's chest. What an adorable amazing sight. Then the scene changes to where I was with a few ladies who know nothing other than cribbing and I wake up. Why couldn't I sleep and what does this dream signify? Any idea?