Answer:
Fiction is a bit difference from fantasy. Fantasy is more on the mystical side with things like magic, supernatural, imagination, etc. While fantasy is fiction, fiction can be a bit more realistic than fantasy fiction. Fiction is based around real events that never happened. Like making up a baseball game that never took place even though baseball is real. Fantasy is more of a imagination thing, like dragons, magic wands, etc.
Ex. of Fantasy: Lord of the Rings or Wonder Woman
Ex. of (Science) Fiction: Godzilla vs Kong or Ready Player One
For this story you need to write, since you said you were being too dreamy, I suggest staying on the thin line between fantasy and realistic events. Think of an event that took place in your life, or someone else's, but change it slightly to how you may like it.
Ex. My brother wouldn't let me eat ice cream when mom wasn't home(Fact) because he said it gave him magic powers and he didn't want the same incident to occur with me(fantasy). So, I'd chase him around the house until my mom got home, stopped him, and let me have some ice cream.(Real ending)
This may not be great and it might to help you at all, but this was just an idea to help you get closer to solving your problem. :)
It can be proven using objective evidence
