Most realistic dream I've ever had

It started with a false awakening, I couldn't see anything at first but my vision slowly returned. I couldn't see a lot, everything was a bit hazy, but I could still put on my t-shirt. I was in my own bedroom, searching for lightswitches, I flipped all switches on the first floor of my house but none of them worked. I looked down the stairs and saw that the ground floor was lit up. Slowly before my eyes, the whole ground floor changed into a swimming pool complex. A girl, looking like one of my classmates was walking up the stairs, crossing me while I went down to look what was going on. When I went down however, my sight was fully returned and everything was as realistic as real life. I could see people swimming in one of the pools and I saw a woman with a baby walking away. I decided to follow her, but when I looked at her again, I saw her sitting next to her child that looked like he was hurt. Her kid looked older now, looking exactly like another classmate of mine. When I looked at him again, he was now a grown man. He told me that he had fallen over, he had tripped. I asked him where he fell on, slowly realising that I knew the answer all along, I got scared and paniced asking where he fell on. He grabbed me, smiled a bit and said: "ON THE GROUND". Then I woke up with a chill down my spine, startled.

While I was still on the first floor of my house I asked myself multiple times if I was dreaming or not, but then I decided that it was real life.
In the swimming pool however, I knew it was a dream and was suprised that everything was so realistic, but I knew that it all meant something.
Also, at the beginning, with the false awakening, I was naked until I put on my shirt.

What could this dream mean? I've honestly never dreamt something like this before and I've never heard some dream character say "on the ground" to me before, but that line was so terrifying in my dream and I don't know why. In my dream I recognised the circumstances as it had happened before, but I seriously have no idea.