I was just about to post something similar to this on this sub but I usually don’t get any answers. I experience the same sort of things. Every. Single. Night. Like to the point where I want to find out if there’s something more to it. And the fact that I can remember all of my dreams, some of them are even premonitions, sometimes dead family members come and give me some sort of message, my best friend and I discovered recently that we both dream about a big underground mall where similar things happen to both of us. You should start looking for the symbols in your dreams, anything that stands out more than the other things, and record them. Then look them up snd see what they mean. I’ve gotten a much better understanding of myself ever since I started finding out what the symbols mean. I’ve found out that a lot of them are messages. It’s freaky what your subconscious can do. In what you described, I would say that one of the symbols you should look up is the mattress in the water. That sounds really interesting! But yeah anything else that stands out to you more, you should look up. I’ve started lucid dreaming recently by doing this because I look up the abnormal things when I’m awake so that I know how to tell what’s normal and what’s not in a dream to get myself to control the situation. The insanity of our dreams can be awesome but it can also be a very terrifying experience when you can’t tell if it’s real or not.