I had a really strange dream experience

It was around 4 years ago, when I was about 17 years old.
I was on vacation with friends at something like a camping site with a tropical waterpark nearby. One day, we decided to visit the waterpark, it was a funny and adventurous experience. 
We've spent a lot of time in there and it was getting late. The waterpark had opened 24/7 and you were also able to sleep in there at an artificial beach with deck chairs, so we took that chance and did that.
The deck chairs were quite uncomfy but they did their job.

After a while I felt asleep and later woke up for a few seconds, according to the brightness it was already morning (I could'nt remember anything else). I closed my eyes and slept again. At least, this is what I thought. Because after I slept a while I really woke up and it was still nighttime with people around me sleeping and I realized, that my first awakening was just a dream??
I was so confused and never had that kind of experience before. Everything in that dream was looking so real, except the time of the day, which did'nt make sense at all. I went to bed at night and woke up at night.

Up until this day, I never had something like this again. It was'nt specifically creepy or something. It was just strange and I did'nt know what happened.

Cheers